Basic methods of psychogenetics. Summary: Modern research methods of human psychogenetics

01.05.2019

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Introduction

1. Psychogenetics, its basic concepts

2. Methods of psychogenetics

2.1 The twin method in psychogenetics

2.2 Genealogical method

2.3 Population method

2.4 Method of foster children

3. Possibilities of applying knowledge from the field of psychogenetics in psychological practice

Conclusion

List of sources used

Introduction

psychogenetics twin psychological

Psychogenetics is a relatively new independent scientific discipline. The main task of psychogenetic research is to study the causes of the origin of individual differences and to clarify the role of hereditary and environmental factors that underlie the striking dissimilarity of people in a wide variety of characteristics (reaction speed, memory, learning success, intelligence level, etc.).

As in all other areas of psychology in psychogenetics, various experimental methods are used to study reactions and behavior, but in the case of psychogenetic studies, the question of the reliability of the results obtained is especially acute. That is, there is a need for a reliable separation of the results of the influence of the genotype and the environment on the reactions of the investigated object.

1. Psihogenetics, its basic concepts

Psychogenetics is an interdisciplinary field of knowledge, bordering "between psychology (more precisely, differential psychology) and genetics; the subject of her research is the relative role and action of heredity and environmental factors in the formation of differences in psychological and psychophysiological characteristics. In recent years, the sphere of psychogenetic research has included and individual development: both the mechanisms of transition from stage to stage, and individual trajectories of development.

The task of psychogenetics is to elucidate not only hereditary, but also environmental reasons for the formation of differences between people according to psychological characteristics. The results of modern psychogenetic studies provide information about the mechanisms of action of the environment to the same, if not more, degree as about the mechanisms of action of the Genotype. In general terms, it can be argued that the main role in the formation of interindividual variability according to psychological characteristics belongs to the individual (unique) environment. Its role is especially high for personality and psychopathological signs. An increasing emphasis in psychogenetic research is placed on the relationship of the socioeconomic level of the family or the length of schooling with the results of testing the intelligence of children. Even such formal characteristics as the parameters of the family configuration (the number of children, the ordinal number of birth, the interval between births) are not indifferent for the individualization of the child - both in the cognitive and personal spheres.

Basic terms and concepts:

1. Heredity is the property of organisms to repeat similar characteristics in a number of generations and to ensure the specific character of individual development under certain environmental conditions. Due to heredity, parents and offspring have a similar type of biosynthesis, which determines the similarity in the chemical composition of tissues, the nature of metabolism, physiological functions, morphological characteristics and other features. As a result, each type of organism reproduces itself from generation to generation.

2. Variability is the opposite of heredity. Variability consists in a change in hereditary inclinations, as well as in the variability of their manifestations in the process of development of organisms in interaction with the external environment.

Heredity and variability are closely related to evolution. In the process of phylogenesis of the organic world, these two opposite properties are in an indissoluble dialectical unity. New properties of an organism appear only due to variability, but it can only play a role in evolution when the changes that appear are preserved in subsequent generations, that is, are inherited.

3. Genetics is the science of heredity and variability of organisms, it reveals the essence of how each living form reproduces itself in the next generation, and how in these conditions hereditary changes arise that are passed on to descendants, participating in the processes of evolution and selection. The subject of human genetics is the study of the phenomena of heredity and variability in humans at all levels of its organization and existence: molecular, cellular, organismic, population, biochronological, biogeochemical.

4. Eugenics - The idea of improving the human species by controlling the gene pool (developed by F. Galton). The problem of increasing the birth rate of gifted people is considered. The main developments are carried out in the following areas: decoding of the human genome, in vitro fertilization, genetic engineering, etc. Based on the data of genetics and psychogenetics.

5. Intelligence - the general ability to learn and solve problems, determining the success of any activity and underlying other abilities; the system of all cognitive abilities of the individual: sensation, perception, memory, representation, thinking, imagination; the ability to solve problems without trial and error "in the mind". The concept of intelligence, as a general mental ability, is used as a generalization of the behavioral characteristics associated with successful adaptation to new life tasks.

6. Genome - a set of hereditary material contained in the haploid set of chromosomes of the cells of a given organism. During sexual reproduction, in the process of fertilization, the genomes of the two parental germ cells are combined, forming the genotype of a new organism. All somatic cells of such an organism have a double set of genes obtained from both parents.

7. DNA - deoxyribonucleic acid - one of two types of nucleic acids that provide storage, transmission from generation to generation and implementation of the genetic program for the development and functioning of living organisms. The main role of DNA in cells is long-term storage of information about the structure of RNA and proteins.

2. Methods of psychogenetics

2.1 Blpurification method in psychogenetics

One of the main types of research in psychogenetics (genetics of behavior), the idea of which was first put forward by F. Galton (1875). The logical foundations of the twin method are as follows:

1) there are 2 types of twins - monozygous (MZ) with an identical genotype and dizygotic (DZ), the genotypes of which differ, as in ordinary brothers and sisters;

2) an approximate equality of postnatal environmental influences is postulated for members of the MH and DZ couples. Comparison of intrapair similarities in MZ and DZ makes it possible to determine the relative role of the genotype and environment in the determination of the trait under study. If the trait is controlled by the genotype, then the similarity of MZ should significantly exceed the similarity of DZ twins. This version of the twin method is called the method of paired comparisons (or contrast groups).

Currently, psychology also uses: the method of separated MZ twins, the method of the control twin, the method of the twin couple. The twin method has disadvantages associated with the features of the pre- and postnatal period of twins' development. A significant reason for errors when using the twin method is the insufficient correctness of the assumption about the equality of environmental influences for the MZ and DZ of twins. There are reliable data on the unequal conditions for the development of MZ in comparison with DZ twins. In this regard, when studying psychological signs using the twin method, it is necessary to carry out a special analysis of those variables of the twin environment that are significant for the formation of the trait under study and the intrapaired similarity in it in twins.

Overcome some of the disadvantages of the twin method. also allows its combination with genealogical and population methods. In addition to solving psychogenetic problems, the use of various versions of the twin method. allows to reveal the psychological content of the concept of "environment" and provides new opportunities for research on the problems of personality psychology, social psychology and other areas of psychological science.

Ratypes of the twin method:

The classic twin method.

In this case, such an experimental scheme is used, in which the severity of the studied trait is compared in pairs of MZ and DZ of twins and the level of intrapair similarity of partners is assessed.

Control twin method.

This method is used on samples of MH twins. Since MZ twins are very similar in many ways, it is possible to make two samples from the partners of MZ pairs, equalized by a large number of parameters. Such samples are used to study the influence of specific environmental influences on the variability of a trait. In this case, the selected part of the twins (one from each pair) is exposed to a specific effect, while the other part is the control group. Since genetically identical people participate in the experiment, this method can be considered a model for studying the impact of various environmental factors on the same person.

Longital twin study.

In this case, long-term observation of the same twin pairs is carried out. In fact, this is a combination of the classic twin method with the longitudinal one. It is widely used to study the influence of environmental and genetic factors in development.

Twin family method.

It is a combination of the family and twin methods. At the same time, family members of adult twin couples are examined. According to the genetic constitution, the children of the MH twins are, as it were, the children of one person. The method is widely used in the study of hereditary causes of a number of diseases.

Study of twins as a couple.

It involves the study of specific twin effects and the characteristics of intra-pair relationships. It is used as an auxiliary method to test the validity of the hypothesis about the equality of environmental conditions for the partners of the MH and DZ pairs.

Sopoputting twins off a non-twinmi.

Also an auxiliary method to assess the significance of the difference between twins and non-twins. If the difference between twins and other people is not significant, then twins and other people belong to the same general sample and, therefore, the results of twin studies can be generalized to the entire population.

Separated Twins Method.

Due to the peculiarities of the development of DZ and MZ pairs of twins, the classical twin method and its varieties are considered to be “non-rigid” experiments: it is impossible to unambiguously separate the influence of genetic and environmental factors in them, since, for a number of reasons, the conditions for the development of twins turn out to be incomparable for a number of reasons. Therefore, the experiments carried out according to the above schemes require additional verification. It can be of two types. Firstly, it is possible to test the hypothesis about the similarity of the environment of MZ and DZ of twins, that is, to prove that the studied characteristic is not affected by differences in the environment of MZ and DZ of twins. But such a check is very difficult and has low reliability. Secondly, the research data can be compared with the results of research on "hard" schemes, which allow you to accurately separate the influence of environmental factors from genetic ones. One of these methods is the separated twins method. This method makes an intra-paired comparison of twins separated at an early age. If MZ twins were separated in a similar way and grew up in different conditions, then all their similarities should be determined by their genetic identity, and the differences - by the influence of environmental factors (see Fig. 2).

2.2 Genealogical method

The genealogical method consists in studying pedigrees based on Mendeleev's laws of inheritance and helps to establish the nature of the inheritance of a trait (dominant or recessive).

This is how the inheritance of individual characteristics of a person is established: facial features, height, blood type, mental and mental makeup, as well as some diseases. For example, when studying the genealogy of the royal dynasty of the Habsburgs, a protruding lower lip and a humped nose can be traced for several generations.

This method revealed the harmful consequences of closely related marriages, which are especially manifested in homozygosity for the same unfavorable recessive alley. In related marriages, the probability of having children with hereditary diseases and early infant mortality is tens and even hundreds of times higher than the average.

The genealogical method is most often used in the genetics of mental illness. Its essence consists in tracing the manifestations of pathological signs in the genealogy using the methods of clinical examination, indicating the type of kinship between family members.

This method is used to establish the type of inheritance of a disease or a separate trait, to determine the location of genes on chromosomes, to assess the risk of manifestation of mental pathology in medical and genetic counseling. In the genealogical method, 2 stages can be distinguished - the stage of compiling genealogy and the stage of using genealogical data for genetic analysis.

2.3 Population method

The terms "gene pool" and "genogeography" belong to population genetics. As a science of the genetic processes occurring in the population of any kind of organisms and of the diversity of genes, genotypes and phenotypes of the population generated by these processes, population genetics dates back to 1908, with the formulation of the first genetic principle, now known as the Hardy-Weinberg principle of genetic equilibrium. It is significant that the genetic processes occurring in human populations, in particular one of their specific manifestations - the stable preservation in many generations of the frequency of such a mendelating trait as brachydactyly, served as an incentive to formulate the principle of genetic equilibrium, which is of universal significance for populations of any species of bisexual organisms. ...

This method is aimed at studying the inheritance of mental disorders in families of patients by comparing the frequency of the corresponding pathology in these families and among groups of the population living in similar natural and climatic conditions. Such groups of people in genetics are called populations. In this case, not only geographic, but also economic, social and other living conditions are taken into account.

The genetic characteristics of populations allows us to establish their gene pool, factors and patterns that determine its preservation and change from generation to generation, which is achieved by studying the characteristics of the spread of mental diseases in different populations, which, in addition, provides the possibility of predicting the prevalence of these diseases in subsequent generations.

Genetic characterization of a population begins with an estimate of the prevalence of the disease or trait under study in the population. These data are used to determine the frequencies of genes and corresponding genotypes in the population.

2.4 Method of foster children

The method of adopted children is a comparison of the similarity in some psychological trait between the child and his biological parents, on the one hand, and the child and the adoptive parents who raised him, on the other.

Methods involve mandatory statistical processing specific to each method. The most informative methods of mathematical analysis require the simultaneous use of at least the first two methods.

The method of foster children is theoretically the purest method of psychogenetics, with the maximum resolution. Its logic is simple: the study includes children who were given up as early as possible to strangers - adoptive parents, their biological and adoptive parents. With the first, children have, as First degree relatives, on average 50% of common genes, but do not have any common environment. With the latter, on the contrary, they have a common environment, but do not have common genes. The similarity between biological parents and their foster children provides a fairly reliable estimate of heritability. The similarity of adopted children with adoptive parents is assessed by the environmental component of the variance. For control, it is desirable to include in the study ordinary families - parents and children living together. One of the very interesting and informative variants of the method is the study of the so-called foster (consolidated) siblings, i.e. several unrelated children adopted by the same family. Given that such children do not have common genes, their similarity (if found) can only be the result of the action of the general family environment.

Reveal two schemes of this method: full and partial. Complete assumes the combination of data obtained from two groups: separated relatives (biological parents and their siblings) and adopted siblings. Partial - either one or another group of data.

A necessary condition for using the method of adopted children is a wide range of environmental conditions in families - adoptive parents, or, conversely, equalization of these families according to one or another characteristics with the subsequent comparison of the individual characteristics of children adopted by them from biological parents who had polar values of the studied trait. The existing ideas about the limitations and conditions of using the method of foster children are described, reasoned and for the most part can be either controlled or taken into account when interpreting the results obtained. Therefore, it is one of the main methods of modern psychogenetics.

3. Possibilities of applying knowledge from the field of psychogenetics in psychologicalNSaction

Psychogenetics solves the question of the origin of human individuality, the existence of "primary", "initial" features of the psyche of the ch-ka, preceding the acquired experience, firstly, and the possible influence of genes on the dynamics of mental development, its individual trajectories, the change of age periods, etc. .d. Secondly.

The solution of these questions determines the concrete scientific methodology and, in addition, turns out to be built into the general outlook of the ch-ka. It is also important for solving applied problems related to diagnostics and taking into account the individual psychological characteristics of a child and an adult. The wrong decision, the wrong understanding of the experimental data of psychogenetics leads to socially undesirable consequences - from the teacher's ignorance of the student's individuality to racist theories.

In addition to studying the etiology of individual psychological differences, psychogenetic research helps to solve a number of scientific problems that are not related to psychogenetics itself. For example, to understand the structure of a particular psychological trait and its changes in ontogenesis can become the basis of age periodization, etc. therefore psychogenetics, its methods and results are very informative not only for differential, but also for general psychology and developmental psychology. There are also questions of psychological and pedagogical practice, for which knowledge about the role of heredity and the environment in the formation of a child's individuality should be important.

The methods available to psychogenetics make it possible to very reliably solve its main task: to clarify the role played by the factors of heredity and the environment in the formation of interindividual variability of psychological and psychophysiological characteristics, individual trajectories of development, etc. In addition, the methods of psychogenetics make it possible to more reliably solve a number of non-genetic problems associated with the allocation of environmental variables that are relevant for various psychological traits, with a more accurate assessment of the effects of external influences, and many others. The movements of a person, their individual characteristics are a very promising object of psychogenetic research, which makes it possible to quite clearly set and fix the psychological conditions for the realization of movement. Change the stimulus environment, task, biomechanics, explore different levels of movement support. From the psychological point of view, among the productive hypotheses, two stand out: 1) about a change in the genotype-environmental relationships in the variability of the phenotypically the same movement when changing the mechanisms of its implementation, i.e. its inclusion in various functional systems. 2) on the dynamics of these relationships in the transition from the individual optimum to the limiting capabilities of the given function. The ultimate goal of psychological research is to understand the etiology and structure of the analyzed trait, to identify factors that affect its individual development, and those characteristics of the environment (cultural, social, group, family or individual) that allow influencing the development, as well as the macro- and microfunctioning of this sign.

Psychogenetic research obeys these goals, studying the genotype and environment in their continuous interaction, combining the methodology and tools of both sciences.

Conclusion

Psychogenetics, unlike conventional psychotherapy, gives very reliable results without tying the patient to the doctor. One of the main provisions of psychogenetics is that our brain is a supercomputer programmed by heredity and our individual consciousness. There is a genetic code that determines the appearance, psychological traits of a person's character and his fate. Alcohol abuse, criminal behavior, and other social behaviors tend to be rooted in genetic predisposition. A person, having understood his genetic code, working on himself, achieves success himself.

An important prerequisite for success is the ability to make decisions. We all do this on a daily basis, but remember that a decision will not be a decision until you act on it. Important decisions such as getting married or investing money can be unsuccessful. The reason is simple: we have not learned (or have not been taught) to defend, making, our decisions and believe in them. Our spirit is almost always positive. He says: "I can," but he can lead to success only if the consciousness does not contradict him. The body has to obey the instructions of consciousness and act accordingly. Action needs a motive, a reason that gives meaning to the action. Therefore, it is imperative that we make decisions and act in the direction we want.

List of sources used

1. Ayala F., Keiger J. Modern genetics: In 3 volumes. M .: Mir, 1987

2. Anokhin AP Genetics, brain and human psyche: trends and research prospects. - M., 1988.

3. Aleksandrov A. A. Psychogenetics: Textbook. - St. Petersburg Peter, 2007 .-- 192 p .: ill. - (Series "Tutorial")

4. Malykh S. B., Egorova M. S, Meshkova T. A. Fundamentals of psychogenetics. - M., 1998.

5. Moskalenko VD, Shakhmatova IV, Gindilis VM Medical and genetic counseling in schizophrenia (guidelines). - M .: Ministry of Health of the USSR, 1981

6.Ravich-Scherbo I.V., Maryutina T.M., Grigorenko E.L. Psychogenetics: Uch. for universities. M .: Aspect Press, 1999

7. Fogel F., Motulski A Human Genetics: In 3 volumes - M .: Mir, 1990. - T. 3. - Ch. 7: Genetics and Human Behavior; Ch. 8: Practical Aspects of Human Genetics and the Biological Future of Humanity.

8 Ermon L., Parsons P . Behavioral genetics and evolution. - M: Mir, 1984. - Ch. 2-5, 7, 11, 12.

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Family Studies - analysis of the similarity of children to each other, children and parents. Binary and ternary relatives are studied more often. they have the same age range for different environments.

Genealogical method.(see genogram method)

Method of adopted children.

It is theoretically the purest PG method with maximum resolution. The study includes children who were given up as early as possible to strangers - adoptive parents, their biological and adoptive parents. With the first, children have, as first-degree relatives, on average 50% of common genes, but do not have any common environment. With the latter, on the contrary, they have a common environment, but do not have common genes. The similarity between biological parents and their foster children provides a fairly reliable estimate of heritability. The similarity of adopted children with adoptive parents assesses the environmental component of the variance. For control, it is desirable to include in the study ordinary families - parents and children living together. One of the very interesting and informative variants of the method is the study of the so-called foster (consolidated) siblings, i.e. several unrelated children adopted by the same family. Given that such children do not have common genes, their similarity (if found) can only be the result of the action of the general family environment.

Reveal 2 schemes of this method: full and partial. Full involves combining data from 2 groups: separated relatives (biological parents and their siblings) and adopted siblings. Partial- either one or another group of data.

A necessary condition for the use of this method is a wide range of environmental conditions in families - adoptive parents or, conversely, equalization of these families according to one or another characteristics, followed by comparison of the individual characteristics of children adopted by them from biological parents who had polar values of the studied trait.

The existing ideas about the limitations and conditions of using the method of foster children are described, reasoned and for the most part can be either controlled or taken into account when interpreting the results obtained. Therefore, it is one of the main methods of modern PG. But in Russia it is not used, because we have a law according to which you cannot give information about adoptive parents.

Twin method.

Twins are children born in the same pregnancy. Monozygous (identical) MZ - 100% of common genes. Dizygotic (fraternal) DZ - 50% of common genes.

Start of research Galton, Thorndike, Meriman. The twins' method was finalized thanks to the works of Siemens. He proposed a basic version of the method, which has become one of the main tools of modern PG, namely, the comparison of intrapair similarities between MZ and DZ, and has developed a reliable method for diagnosing zygosity, which involves the simultaneous assessment of many traits, and not individual ones, as was done before. This method became known as the polysymptomatic method.

The modern method of twins - there are 2 types of twins: MZ and DZ. For reasons unclear to science, sometimes in the early stages of division, the zygote gives rise to 2 embryonic structures, from which 2 full-fledged organisms develop further. DZ from a genetic point of view - siblings, siblings.

At the same time, the equality of environmental influences in the pairs of MZ and DZ is postulated: it is believed that the co-twins of both MZ and DZ, being children of the same family, of the same age and of the same sex (opposite-sex couples are usually not included in the research), develop in the same environment, and therefore, its influence on the formation of individual characteristics of the psyche is the same for members of both the MH and DZ couples. In this case, the researcher obtains an ideal scheme of a two-factor experiment: the influence of one factor (environment) is equalized, which makes it possible to isolate and evaluate the influence of the second factor (heredity). Operationally, this means that the intrapair similarity of genetically identical MZ of twins should be higher than that of non-identical DZ, if the studied trait is determined by heredity: the same heredity - similar values of the trait (MZ); different heredity (DZ) - the similarity of the pair's twins is below. This is the basic version of the twin method. Intra-pair similarity is assessed mainly using the Fisher intra-class correlation coefficient.

Twins method limitation associated with 2 groups of factors: pre- and postnatal. Prenatal- depending on how early the zygote began to divide into 2 embryonic structures, the MZ may have different combinations of amniotic membranes: separate amnions, but one chorion: both membranes can be separated, etc. In some cases, one twin may have a better blood supply than the other. This will lead to greater maturity and greater birth weight, and then - to the better development of this twin in the initial period of ontogeny. This means that the intrapair similarity of the MH is reduced due to physiological rather than genetic differences - one of the cases when we can talk about congenital, but not hereditary features. In the study, this will reduce the intra-pair correlation of MH and, unjustifiably, reduce the heritability coefficient. The possibility of prenatal influences that reduce the intra-pair similarity of the MH should be borne in mind, but they are not decisive. Much more important - features of the postnatal environment of twins.

Research evidence suggests that the MH environment is more similar than that of DZ + parents treat MH more similarly than DZ. The developmental situation of twins is multifaceted, the specificity of the situation lies in the fact that twins often feel like members of a couple rather than separate individuals. The resulting effect of twins can have a significant impact on the psychological characteristics of twins. The pairing of children - twins can be manifested already in early childhood.

All of this is sometimes interpreted as circumstances that compromise the method. However, in order to accept such a conclusion, it is necessary to decide: is environmental similarity a cause or an effect? Does the degree of environmental similarity / difference affect the degree of psychological similarity between the partners of twin couples? According to the works of some authors, a more similar treatment of children by parents - MH is a consequence, a reaction to their genetic identity, and not an external cause that forms the nongenetic intra-paired similarity of MH of twins and thereby overestimates heritability.

Varieties of the twins method.

Separated Twins Method. It consists in assessing the intra-paired similarity of the trait under study in twins separated in childhood and, therefore, brought up in different environments. The most valuable are pairs of MH, separated in the first months or years of life: 2 genetically identical people grow in different environmental conditions. Then their similarity, if it is stated, cannot be explained by the similarity of the environment, and the resulting correlations are a direct measure of the heritability of a trait. This is a kind of critical PG experiment.

Family method MH (semi-sibling method). It consists in comparing children in families where mothers or fathers are MOH. These children have a very peculiar genetic status: an aunt (or uncle), from the genetic point of view, is the same as the father (mother), i.e. they, not being siblings, are not also cousins, since they have only one genetically different parent, therefore they are called semi-siblings. The main task of the method is to identify the maternal effect. Those. the predominant influence of the mother on the phenotype of the offspring, which arises not only due to the transfer of genes, but also for other reasons, which include psychological, postnatal factors (identification of the child with the mother, the peculiarities of their interaction), and biological, intrauterine (the state of the maternal organism during pregnancy , cytoplasmic heredity). The presence of a maternal effect in the psychological trait should manifest itself in a greater similarity of children with mothers - MH, compared with children who have MH fathers. In addition to the maternal effect, this experimental model allows a more detailed study of the phenomenon of assortativity, i.e. non-random selection of married couples, and adhesion to the floor. In the latter case, half-siblings - boys should be more similar, if monozygous - to their mothers (since each of them received their only X chromosome from genetically identical women), less similar if fathers. For girls - half-siblings, the picture should be the opposite.

The main limitation of the method: genetically identical parents can create a similar environment in their families. This version of the method can successfully solve some particular issues, however, to separate the genetic and environmental dispersion of a trait, it has a lower resolution than other PG methods.

Control twin method. MZ - genetically identical people who had a common embryonic and family environment under normal conditions - are ideal control to each other. If the MH group is divided into 2 samples so that each includes 1 twin from each pair, then the researcher will receive a unique situation - 2 samples, equalized both for the genetic constitution and for the main environmental parameters. Further, you can, for example, train one group and not another, or train them at different ages. (For example, it has been shown that learning using the “models” method is more effective than simple copying: not only does constructive activity itself improve, but other mental functions of the child are also rebuilt). There are very few such works, but they are also divided into 3 groups:

1.the earliest work that explores the interaction between maturation and training, with twin partners being taught the same thing, but at different ages.

2. the effectiveness of different teaching methods is compared, as an example is the study of teaching to read.

3. the question of how significant can be the differences created by the environment in genetically identical individuals. Experimental methods of changing environmental influences.

Twin pair method. It is built on the "couple effect" or "twin effect". 2 struggling tendencies: to identify with your twin and, conversely, to individualize each member of the couple.

1 - leads to the feeling of oneself first as a member of a couple and only then as a separate person.

2 - in extreme cases, it can lead to a pronounced conflict relationship between twins, a kind of protest against a second one of the same kind. With age 1, the tendency usually weakens, giving way to the second, and in men this process is easier than in women.

Using this method, 2 tasks are solved:

1. general psychological - since an individual exists only within certain systems of communication (for example, in a dyad), so far as a twin pair, especially MH can be an excellent model for studying the processes of individualization, the influence of specific environmental factors on the formation of certain psychological traits, etc.

2. check: the validity of the twin method itself, as well as the postulate of the equality of environmental influences in the pairs MZ and DZ + the question of whether the environment of the twins is representative of the environment in which single-born children develop. If the conditions for the development and life of twins are highly specific, have their own inherent patterns, then the twins cease to be a sample representative of the general population, and cannot be used to study general patterns.

3. in addition, excessive, uncompensated identification of oneself with one's twin, or a couple as a whole, as a unit, leading to a lack of personal identity, can cause the formation of personality traits that impede social adaptation both in childhood and adulthood.

Foster Child Methodallows you to find out what more affects the development of a trait - genetic inclinations, or a certain influence of the environment. To do this, study children who are taken up in other families. The method is based on comparing their similarities with biological parents and those who adopted them. Similarity with biological parents is interpreted as evidence of genetic influences, similarity with adoptive parents - as an indicator of the influence of the general environment. As an example, let us give a study of the role of the genotype and the environment in the formation of such a trait as the IQ(IQ). It was shown that if the coefficient IQ mother was more than 120 points, then the children of this group, given to foster care in other families, subsequently not a single case with IQ less than 95, and in 44% of children it was also more than 120. If you look at the IQ of those adopted children whose biological mothers had IQ less than 95 points, it turns out that as a result there was not a single child with an IQ of more than 120 points, and in 15% it was less than 95. Such data indicate a large role of the genotype in the development of this trait.

When using the method of adopted children, the correlation in the development of the studied trait between biological parents and their children raised in other families is determined. The presence of similarity in the development of a trait under such conditions indicates the contribution of the genotype to the development of a trait (in children and biological parents, 50% of common genes). If possible, then determine the correlation between separated brothers and sisters, given to other families or left with biological parents. Here, too, there is a lack of general environmental influences and the similarity of the genotype.

The same calculations are carried out for adopted children and their adoptive parents. The similarity in the development of a trait in this case indicates the great role of environmental influences, since general heredity is excluded. Another option is to compare the adopted children with the adoptive parents' own children. Comparison of children who are not relatives, but brought up in the same family, makes it possible to directly assess the contribution of the general environment to the variability of the trait; it is enough to simply calculate the correlation coefficient of its severity.

For the greatest purity of the study, it is necessary to select cases of the earliest possible adoption, then the impact of another environment will be minimal.

Another possible source of bias when using this method is related to the fact that families in which foster children are raised are not entirely representative. This is due to a number of requirements for adoptive parents. The environmental influences that are represented in these families are characteristic mainly of the middle class; accordingly, the environmental impacts in conditions of extreme poverty and deprivation remain underestimated. The underrepresentation of environmental influences related to various risk factors can affect the research results.

Introduction

Almost all of us are carriers of certain genetic defects, and these defects arise constantly, throughout our entire life. Where do they come from? Is it possible to consider the burden of genetic defects as a predestination, maybe this burden is a consequence of the Fall? Is this really the result of heredity or the influence of the environment in which we live?

These questions are of concern to millions of people, because genetic defects become the causes of severe psychophysical diseases that are difficult to treat, and many are generally incurable.

Psychogenetics is a field of knowledge bordering between psychology and genetics, characterizing the relative role and interaction of genetic and environmental factors in the formation of a person's mental individuality. (SSU, p. 8)

The problems of psychogenetics have been and continue to be dealt with by scientists from various branches of science - these are biologists, and geneticists, and doctors, and theologians, and teachers. F. Galton's research laid the foundation for psychogenetics, thanks to the works of G. Siemens, the method of twins was finalized, which has become one of the main tools of modern psychogenetics. In the two-volume edition of the selected works of KD Ushinsky there is a special chapter “Heredity of habits and development”, where he recognizes the possibility of inheriting the nervous inclinations of “habits”, which can subsequently, depending on the circumstances, either develop or die out. In 1962, J. Watson, F. Crick and M. Wilkins discovered the structure of DNA, which predetermined almost all subsequent development of biology and genetics. Professor Ted Peters paid attention to the problem of genetic determinism from a theological point of view, considering as factors of development not only the environment and heredity, but most importantly - the personality itself, which is able to control genes.

Thus, relevance This topic is due to the need to study the role of heredity and environmental factors in the formation of individual psychophysical characteristics, in order to determine the possibility of successful application of the data obtained not only in medicine, but also in Orthodox pedagogy.

Target of this work - a theoretical review of modern research methods of human psychogenetics and the definition of the field of application of these studies in Orthodox pedagogy.

Object of study - psychogenetics in a pedagogical context.

Subject of study - modern methods of human psychogenetics.

The implementation of this goal involves the formulation and solution of the following tasks :

1) Trace the development of psychogenetics from its origins to the present;

2) Establish a connection between psychogenetic research and pedagogy;

3) Describe modern ideas about the complex influence of heredity and the environment on the process of forming a child's personality;

4) Study and characterize the methods of psychogenetics;

5) Compare existing techniques and analyze the limitations of each method;

6) Identify the areas of application of these studies in Orthodox pedagogy;

Work structure ... The research consists of an introduction, two chapters, a conclusion, a bibliography, an appendix.

§1.1. Psychogenetics as a scientific discipline.

Stages of development of psychogenetics.

Psychogenetics is an interdisciplinary field of knowledge, bordering between psychology (more precisely, differential psychology) and genetics; the subject of her research is the relative role and interaction of factors of heredity and environment in the formation of individual differences in psychological and psychophysiological characteristics.

Psychogenetics has recently emerged as an independent science. The beginning of its formation is associated with the name of the English scientist F. Galton. In 1865, he published an article "Inherited Talent and Character", which opened a series of his works on human heredity, including "Hereditary Genius: Its Laws and Consequences" (1869), "The History of Twins as a Criterion of the Relative Strength of Nature and Upbringing" ( 1876). Thus, F. Galton became the founder of the psychology of individual differences and psychometrics. Period from 1865 to 1900 can be defined as the time of origin of psychogenetics. The next period from 1900 to the end of the 30s. characterized by the development of the methodology of psychogenetics, the formation of psychogenetics as an independent scientific discipline and the accumulation of experimental results. In the 40s. interest in psychogenetics decreased, which was associated with the war, the spread of racism, which was covered by genetics, the lack of new ideas in the doctrine of heredity. With the discovery in 1953 of the molecular basis of heredity, the prerequisites for further success in psychological research are created. At this, third stage - until the 60s. - psychogenetic studies of intelligence, various mental anomalies were carried out. This stage can be defined as the time of accumulation of empirical material. In 1960, the scientific society "Association of Behavioral Genetics" was created and the journal of this society "Behavioral Genetics" began to be published. This year is seen as the beginning of the modern stage in the development of modern psychogenetics.

In the same year when F. Galton published his works, essays by V.M. Florinsky "Improvement and degeneration of the human race" (1865). One of the important means of improving the "human breed", he considered the deliberate selection of married couples, so that in the presence of one of the parents of a pathological symptom, oppose the normal characteristic of the other parent.

The first in Russia study of the hereditary nature of mental properties belongs to Academician K.F. Wolff, who in the 19th century studied the "theory of freaks", including the transmission of anomalies to offspring. The nature of individual characteristics was also of interest to teachers. In the works of K.D. Ushinsky has a section called "heredity of habits and the development of instincts."

Experimental research was carried out mainly in two scientific centers: in Petrograd - the Bureau for Eugenics and in Moscow in the Medical-Biological Institute (since 1935. Medical-Genetic). In 1937, the Medical Genetic Institute was closed and work in the field of psychogenetics ceased until the 60s.

Domestic psychogenetic research resumed within the framework of studying the nature of interindividual differences in the properties of the nervous system in the laboratory of B.M. Teplova, then V.B. Nebylitsyn. Since 1972, these studies have been continued in the laboratory of I.V. Ravich-Scherbo at the Research Institute of General and Pedagogical Psychology of the USSR Academy of Pedagogical Sciences. In our time, psychogenetic research is carried out in many scientific institutions in our country.

1.2. The importance of psychogenetic research for pedagogy

The uniqueness, the uniqueness of the psychological appearance of each person is one of those obvious phenomena of our psyche, which is most vigorously discussed and studied by various sciences. This is philosophy, psychology, genetics, medicine, and many applied sciences and, of course, pedagogy.

The teacher in his work encounters the fact that people are psychologically different, and seeks to understand the origins of this diversity. This intuitive understanding of the psychological dissimilarity of people and the desire to "guess", diagnose individuality are rooted in the deep past. In the treatise "Moral characters", the author of which was Aristotle's friend and successor Theophrastus, 30 bright characterological types and their specific manifestations are described, it contains descriptions of a large number of informative psychodiagnostic indicators. Physiognomy has existed since ancient times (from the Greek words meaning: "nature", "natural inclinations" and "knowledgeable", "insightful") - the doctrine of recognizing natural individual characteristics, in particular character, according to the physical characteristics of a person, his appearance. In the middle of the 17th century. the Italian physician C. Baldo published the first work on graphology "Discourses on the way to recognize the customs and qualities of those who wrote from his letter." The study of characterological types by physical characteristics, handwriting and other indicators continues now, it is used to solve a variety of problems, including psychological and pedagogical.

In modern pedagogy, there is the concept of a personality-oriented approach in teaching and upbringing, its implementation presupposes not only that the teacher has knowledge about a person's individuality, but also the possession of methods for diagnosing it. On this basis, the teacher has the opportunity to predict the further development of the personality, as well as to correct and optimize it.

An example of the dependence of the effectiveness of learning on the individual characteristics of a student is the work of the German researcher G. Klaus "Introduction to Differential Psychology of Learning" [Klaus G. Introduction to differential psychology of learning. M., 1987.]. The data of his research suggests that, knowing the dependence of educational success on certain personality characteristics that are not directly related to this activity (i.e., not related, for example, to knowledge and skills in this area), it is possible to optimize a person's activity, but with one obligatory condition: if the basic individual characteristics are ontogenetically stable.

The data of psychogenetic research allow the teacher to competently organize work with children. This is especially true for corrective work with students with mental development disorders. It is believed that among children, one in ten children is at risk of an abnormal developmental type. This can be criminogenic behavior, episodes of depression or anxiety, as well as a violation of intellectual or emotional development: from a rare form of autism to a specific learning disability, as well as in a state bordering on the clinic and the norm - attention deficit hyperactivity disorder. (SSU, p. 13)

It is very important for a teacher to know the features of the manifestation of such diseases, to differentiate them, to master the techniques of working with children prone to mental illness. This can be done by the data of psychogenetics. For example, for a general assessment of a child's developmental delay, a teacher can use the definition of the intelligence quotient. The obtained values make it possible to qualify the degree of mental disorder and choose the best ways to solve it. Knowing the peculiarities of the intellect, perception and memory of a child with autism, the teacher can productively conduct correctional work.

Thus, the data of psychogenetic studies are a necessary tool both in the correctional and in the educational work of the teacher. They serve as both a theoretical aid and a practical basis for identifying certain personality traits, which helps the teacher to optimize the educational process.

1.3. Modern ideas about the complex influence of heredity and the environment on the process of forming a child's personality

As already indicated in the introduction, psychogenetics deals with the problems of the role of heredity and the environment in the formation of mental and psychophysiological properties of a person. The aim of the research is to try to find out how genetic and environmental factors are involved in the formation of the phenotype. More recently, psychologists believed that the characteristics of human behavior are almost entirely determined by the influences of the environment in which development takes place. The merit of psychogenetics is that it drew the attention of scientists to the nature of individual differences in humans. (Alexandrov, p. 28)

Psychogenetics has shown that absolutely identical influences can lead not to an increase in similarity, but to the emergence of differences between people. Different genotypes under the influence of the same environmental influences can form different phenotypes. For example, the same environmental influences are experienced differently by family members and can lead to differences for many mental traits. (Alexandrov, pp. 28-32)

Moreover, a simple separation of genetic and environmental influences is practically impossible in some cases. The genotype can actively interact with the environment to the extent that the effects of the environment can, to some extent, be predetermined by the characteristics of the genotype. Often, environmental influences, which are, for example, a risk factor for the emergence of some pathology, are most clearly manifested in those individuals who have a genetically determined predisposition. (Alexandrov 28-32)

In the context of the psychogenetic study of environmental characteristics, three points are extremely important.

First, genetic research has consistently pointed to the critical role of environmental factors in shaping psychological differences between people. Numerous psychogenetic works have clearly shown how important the role of genetic factors is in explaining interindividual variability for a variety of traits. In some cases (for example, for the variability (variability) of indicators of intelligence), genetic influences explain 50% of the phenotypic variability. What, however, explains the remaining 50%? The answer to this question is very simple: for the most part, the environment is responsible for the remaining 50%, or rather the features of the environment in which carriers of genotypes develop and live.

Secondly, in the context of the genetics of quantitative traits, the concept of the environment is defined much broader than in psychology. According to this definition, the concept of "environment" includes all types of environmental influences - family, individual and any others (including its physical and physiological components, perinatal conditions, diet, early childhood diseases, etc.), while in psychology, environmental conditions are usually equated only to the socioeconomic and psychological conditions of the child's growing up.

Third, psychogenetics focuses its efforts on the question of what is (at a given moment in a given population), and not on the question of what might happen. For example, the high values of the heritability coefficient obtained in the study of interindividual variability in height, states the fact that at a given time in a given population, growth dispersion is explained mainly by genetic differences between members of this population (which is). However, certain environmental interventions (for example, changing the diet and increasing the amount of vitamins in the diet) can affect the formation of interindividual differences in the population for such a highly heritable trait as growth (which can happen).

In the last 5-10 years, psychogeneticists have discovered three very unexpected phenomena:

a) in children growing up in the same family, the environment forms differences rather than similarities;

b) many psychological instruments (questionnaires, observational data, etc.) used to measure environmental characteristics show an unexpectedly high level of genetic control.

c) in the decomposition of the phenotypic dispersion of the overwhelming majority of psychological characteristics studied by psychogenetics, the role of the general family environment turns out to be insignificant.

All this makes it possible to formulate a hypothesis that people create or find certain environmental conditions corresponding to their genotypes, and are not passive "victims" of their genes or "inherited" environment. In other words, the individual genotype turns out to be the "constructor" of the individual environment.

Thus, the study of the genotype is impossible and inadequate without studying the environment in which it is located. The time of opposition of "two factors" - genes and environment - is over. Today we know enough to assert without a shadow of doubt: the emerging individuality is not divided into what is in it from the environment and what is from the genotype. Development is essentially a process of intertwining and interaction of genes and the environment, development is their interaction. (Ravich-Scherbo, 122-128)

2.1. General characteristics of psychogenetic methods

Psychogenetics, along with other psychological disciplines, such as differential psychology, studies individual differences between people. So why does psychogenetics need its own methods? The thing is that psychogenetics has a common object of research with these disciplines, but its own specific subject. Own methods of psychogenetics are necessary precisely in order to assess the contribution of genetic and environmental factors to the phenotypic diversity of a particular trait in a population.

The methods of psychogenetics are experimental schemes that are based on comparing people with different numbers of common genes in a parallel analysis of environmental conditions that are important for the formation of the studied traits. For assessing genetic influences, the ideal situation is when genetically identical people were brought up in a different environment, and for assessing environmental influences, when genetically unrelated people were brought up in the same environment. Ultimately, studies carried out by psychogenetic methods make it possible to judge such population characteristics as:

Heritability coefficient, or the proportion of variability
trait in a population arising from variability
genotypes.

General environment indicator, common environment variance, or
the proportion of phenotypic variance arising from
variability of the general environment. Phenotypic variance is an indicator of the deviation of intelligence from the mean in the sample.

Indicator of the individual environment, individual-environmental variance, or the proportion of phenotypic variance arising from the variability of the individual environment.

Currently, three main methods are used in psychogenetics - the family method, the method of foster children and the method of twins. The method of adopted children cannot be applied in our country, since there is a secret of adoption guaranteed by law. In psychogenetics, population and genealogical methods are also used, but they have a low resolution. All five of the listed methods of psychogenetics will be described below. (Pankratova, p. 5-8)

2.1. Population method

The population method is based on the comparison of representatives of different populations. Under the population is meant "a set of freely interbreeding individuals of the same species, occupying a certain area and having a common gene pool in a number of generations" (Shevchenko, Topornina, Stvolinskaya, Human Genetics. Textbook for universities. 2002, p. 23). The genetic structure of a population is preserved provided that there is a free, random formation of parental pairs within the population and no marriages are concluded with representatives of other populations. In psychogenetics, representatives of different races are most often compared - Caucasoid, Negroid and Mongoloid. An important point is that population groups are studied taking into account such factors as natural and climatic, economic, social and other living conditions. (Pankratova, p. 9) Genetic characteristics of populations allow us to establish the gene pool of a population, factors and patterns that determine the preservation of the gene pool or its change in generations. Studying the features of the distribution of mental properties in different populations makes it possible to predict the prevalence of these properties in subsequent generations. The genetic characterization of a population begins with an estimate of the prevalence of the studied trait or trait in the population. According to the data on the prevalence of the trait, the frequencies of genes and the corresponding genotypes in the population are determined. (SSU, p. 35)

An example of the population method of psychogenetics is the study of the intellectual abilities of US secondary school students. Among them - 1631 representatives of the Caucasian race and 730 representatives of the Negroid race. It was found that the distributions of IQ scores for blacks and whites overlap strongly and that the difference between the average IQs of blacks and whites is about 15 units (see Figure 3). To explain these results, a genetic hypothesis was proposed, according to which the higher average IQ of whites, compared to blacks, is associated with a difference in their gene pools. (Fogel F., Motulsky A. Human genetics. T. 3. M., 1990. with. 137)

The analysis of the results of a population study is as follows: if representatives of different races, who are carriers of different gene pools, differ significantly from each other in some psychological or psychophysiological characteristics, then the differences between people in these characteristics are associated with genetic factors. Such reasoning is, to say the least, controversial, since representatives of different races can differ significantly from each other and due to different environmental conditions. To assess the contribution of genetic factors, it is necessary to compare representatives of different races living in identical environmental conditions, that is, having the same families, education, professional opportunities, etc. But it is unlikely that people living in different cultures have such comparable conditions.

On the other hand, real populations are rarely completely isolated: people move from one population to another and enter into mixed marriages. For example, the ancestors of modern blacks in the United States were taken out of Africa 300 years (about 10 generations) ago. Scientists have calculated that the flow of genes from the white population to the Negro was at a rate of 3.6% per generation. Thus, in the modern black population of the United States, the share of genes of African ancestors is 0.694 of the total number of genes. In other words, African blacks inherited about 30% of genes from the white population. As a result, differences within a population become wider than differences between populations. (Pankratova, 9-11)

Thus, the population method of psychogenetics is used to determine the genotypes of populations, to predict the mental properties of populations in subsequent generations. But this method has a low resolution due to the impossibility of creating identical conditions for different populations and the impossibility of isolating them from each other - all this becomes a limitation of the method and an obstacle in establishing the population gene pool.

2.3. Genealogical method

The genealogical method (analysis of pedigrees) is based on the comparison of representatives one family in a number of generations. In order to make this comparison more descriptive, the pedigree is depicted graphically using special characters (see Figure 4). When drawing up genealogists cheskogo tree there are certain rules. So, the symbols of representatives of one generation are located in one line of the pedigree. The numbering of generations occurs in the direction from previous generations to the present and is affixed to the left of the pedigree in Roman numerals. Children in each family are labeled from left to right in birth order and are labeled with numbers or years of life.

When analyzing the pedigree, the researcher analyzes the manifestation of the trait in a number of generations. If the sign repeats in a number of generations, it is concluded that genetic the nature of individual differences on this basis. For example, when analyzing the ancestry of the Bernoulli family, we see that in a number of generations there are people with mathematical abilities (see Figure 5). For a researcher, such a number of mathematicians in a family speaks of the genetic nature of mathematical abilities. But if we start to study the biography of the Bernoulli family, we will find a lot environmental factors that influenced the formation of mathematical abilities (for example, a father was a teacher of his sons in mathematics, an uncle attracted nephews to his work in mathematics, the family had a common circle of mathematician friends, etc.). On the other hand, it is not entirely clear to what extent the mathematical abilities of different representatives of the Bernoulli family are equivalent, since the presence or absence of a sign is assessed, and not the degree of its severity.

Thus, the genealogical method does not allow exactly to answer the question, due to genetic or environmental factors, the repetition of the studied trait occurs in a number of generations. But this method allows you to determine inheritance type all sorts of signs (for example, diseases or abnormal features of appearance) and make a forecast for the future. The bearer of the feature of interest to us is called proband. In a series of generations, people with a trait (for example, affected by this disease) are designated on the family tree. Next, the logic of the repetition of the trait is analyzed and the type of inheritance is established. For example, Figure 6 shows the pedigree of a person with hypertrichosis. Hypertrichosis is the presence of hairs along the edge of the auricles. As can be seen from the pedigree, this trait is always passed on to sons and never to daughters, that is, we can talk about a Y-linked type of inheritance. (Pankratova, pp. 11-14)

Thus, genealogical research by itself, without combining with other methods, has a very low resolution and does not allow to reliably "separate" the genetic and environmental components of the variance of a psychological trait. Although, when combined with other methods, for example, with twin methods, family data allow us to solve issues that cannot be solved without them (for example, to clarify the type of inherited transmission - additive or dominant), or to control environmental variables (for example, the family and individual environment, the effect twins). (Ravich-Scherbo, p. 162)

The genealogical method can be useful for teachers in the educational process for the competent selection of methods and principles of teaching, organizing correctional work with children.

2.4. Family method

Some researchers, among the methods of psychogenetics, single out the family method, which involves comparing representatives one family, which have a different number of genes in common (see Figure 7). Family members (at least two groups of relatives) are compared in pairs: brothers and sisters (siblings), cousins and sisters, second cousins, parents and children, grandmothers and grandchildren, grandfathers and grandchildren, aunts and nephews, uncles and nephews, etc. All these pairs of relatives by the number of common genes can be divided into closer (have more common genes) and less close (have fewer common genes) relatives (see Table 1).

The logic of the method is that if, according to the studied trait, closer relatives (having more common genes) are more similar in comparison with less close relatives (having fewer common genes), then individual differences in this trait are associated with genetic factors.

But the greater similarity of relatives with a greater degree of kinship may be associated with environmental factors, since closer relatives have, as a rule, more similar living conditions. In order to increase family reliability studies, it is necessary to compare samples of less close relatives who do not usually live together. For example, comparing cousins with siblings with second cousins will make it possible to more accurately determine the role of genotype and environment in the formation of individual differences in this trait than comparing native siblings with cousins.

In addition, in a family study, there are problems when comparing representatives different generations(for example, parents and children). These problems are due to the fact that the compared relatives are separated by a rather large age interval. On the one hand, the influence of the genotype on the studied traits can change with age. On the other hand, when diagnosing people of different ages, you can get incomparable results. To overcome these difficulties, it is necessary to conduct a survey of representatives of different generations at the same age. This is possible only when conducting a longitudinal study, that is, when retesting representatives of the younger generation, when they reach the age at which representatives of the older generation were examined. (Pankratova 14-17)

Thus, the family method makes it possible to accurately assess the contribution of heredity and environment to the formation of individual differences. However, family research itself has a very low resolution, but the integration of several methods at the same time allows to resolve controversial issues in the interpretation of the results. (Pankratova, pp. 28-29)

2.5. Foster Child Method

When using the method of adopted children, one compares foster children with biological parents and with parents- adoptive parents. For the study, children are selected who are given up as early as possible to be raised in other people's families (preferably in the first days of life). An adopted child with his biological parents has 50% of common genes, and with his adoptive parents - a common environment. Thus, if the adopted child is more similar in some psychological or psychophysiological trait to biological parents, then the researcher concludes that individual differences in this trait are more related to genotype. And if the adopted child is more like adoptive parents, then these differences are associated with environment. (Pankratova, p. 17)

The first work carried out using this method was published in 1924. The results, from the author's point of view, indicate that the intelligence of adopted children depends more on the social status of biological parents than adoptive ones. However, as noted by R. Plomin and co-authors, this work had a number of defects: only 35% of the 910 children surveyed were adopted before the age of 5; the measurement of mental abilities was carried out on a rather rough (three-point in total) scale. The presence of such flaws makes it difficult to analyze the study meaningfully.

25 years later, in 1949, the first work appeared, made according to the complete scheme of the method. It was followed by others, the largest of which were two modern programs: the Texas and Colorado foster child research projects.

One of the very interesting and informative variants of the method is the study of the so-called foster (consolidated) siblings, i.e. several unrelated children adopted by the same family. Given that such children do not have common genes, their similarity (if found) can only be the result of the action of the general family environment.

There are two schemes of this method: full and partial. The first involves combining data from two groups: separated relatives (biological parents and their children given to adoptive parents; separated siblings) and adopted siblings; the second is either one or the other group of data. In the first case, as R. Plomin and his co-authors write, there are “genetic” parents (biological parents and their abandoned children), “environment” parents (adoptive parents with their adopted children) and, as a control, an additional group of “genetic plus environment” parents (ordinary biological family). Comparison of these three groups makes it possible to reliably "separate" the factors that form family similarities.

Using the method of foster families, it was shown that in an equally good environment, the distribution of IQ estimates for foster children is shifted towards high values if biological parents had high intelligence, and towards low values - if they had reduced intelligence. (Results of this kind prompted a witty remark from one of the psychogeneticists: "It is best to assume that intelligence is 100% dependent on genes and 100% on the environment.")

Possible limitations of the method are related to several problems. First, how representative of the population is the group of women that give birth to children? But it is controllable. For example, in the largest program, the Colorado Study of Foster Children, all participants (245 biological parents, their abandoned children and adoptive parents, as well as 245 control families with biological and adoptive siblings) were representative of the general population in terms of cognitive characteristics, personality traits, family environment. , educational and socio-economic status. The authors note that even if by some parameters the samples turn out to be deviating from the population distributions, this should be taken into account when interpreting the results, but does not give a reason to consider the method invalid.

Secondly, a more specific question arises about the selectivity of placing children in foster families: are there any similarities between siblings and foster parents in some way? It is clear that such similarity will overestimate the correlation in child-adoptive pairs, if the studied trait is determined by heredity, and in child-biological parent pairs, if it is more determined by the environment. In any case, estimates of the genetic or environmental component of the variability of a given trait will be distorted.

Thirdly, there is the problem of perinatal influences of the maternal organism on the characteristics of the unborn child, which should increase the similarity between the mother and the given child due to intrauterine, but environmental, and not genetic factors. According to some researchers, by the time of birth, the human fetus already has some experience. If this is the case, then the similarity of the biological mother to the given child may have a non-genetic origin. As a result, some researchers even believe that the method of foster children is very informative for studying various postnatal environmental influences, but not for solving the genotype-environment problem.

There are also more subtle circumstances that are important for evaluating the method. For example, the possibility of the formation of subjective legends about the parents in a situation where the child knows that he is not in a given family. In experimental work, this creates an uncontrollable hindrance, since such a legend can turn out to be a rather serious educational factor.

In our country, it is impossible to use this method, since we have a secret of adoption guaranteed by law. This is a humane, pedagogically absolutely correct decision, but it means that the researcher does not have the right to seek information either about adopted children or, moreover, about their biological parents.

Thus, the existing ideas about the limitations and conditions of using the method of foster children are described, reasoned, and for the most part can be either controlled or taken into account when interpreting the results obtained. Therefore, it is one of the main methods of modern psychogenetics. (Ravich-Scherbo, p. 162-165)

2.6. Twins method

The first attempt to use twins to solve the problem of "nature and nurture" belongs, as already mentioned, to F. Galton, who intuitively foresaw what became a scientific truth and a serious research method only several decades later. The fascination with twins was a fairly typical phenomenon in the science of the late 19th - early 20th centuries. Studied their biology, pathology, origin, etc. We also find twin works in many famous psychologists of that time: E. Thorndike, S. Merriman, G. Siemens and others (Ravich-Scherbo, p. 165)

There are several varieties of the twin method (see table 2). Classical version of the twins method is based on a comparison of two types twins - monozygous (MH) and dizygotic (DZ). Monozygotic twins develop from one fertilized egg (from one zygotes), which in the early stages of division gives rise to two organisms (necessarily of the same sex). Thus, MZ twins are the only people on Earth with the same gene sets. (100% common genes). In turn, dizygotic twins develop from two fertilized eggs (from two zygotes). From a genetic point of view, DZ twins are siblings with an average 50% common genes. The difference lies only in the simultaneous development and birth of two children of the same or different sex. Note that heterosexual pairs of DZ twins are included in a psychogenetic study to assess the influence of the gender factor on individual differences.

The twin method is based on two basic assumptions. First: it is supposed equality environmental influences on the development of MH and DZ of twins. If this postulate is violated, the values of heritability indicators and other components of phenotypic variance are distorted. Second: absent systematic differences between twins and single children. If this postulate is violated, the conclusions of the psychogenetic study cannot be generalized to the entire population.

When using the classic version of the twins method, first two groups are recruited, consisting of members of the MH and DZ of twin pairs. Then, the similarity in pairs of MZ and the similarity in pairs of DZ twins are assessed. (intra-pair similarity) on the basis of study. After that, the intra-paired similarity in the group of MZ twins is compared with the intra-pair similarity in the group of DZ twins (see Figure 9).

Logics method is as follows. MZ twins have 100% of common genes, DZ twins have an average of 50% of common genes. At the same time, the equality of environmental influences on the development of MH and DZ of twins is postulated. The similarity between members of twin pairs is determined by both genotype and environment. Consequently, if the measure of intrapair similarity of MZ of twins is higher than the measure of intrapair similarity of DZ, then individual differences in the studied trait are more associated with genetic factors.

When conducting a psychogenetic study using the twins method, the question may arise about zygosity twins, because it is not always easy to determine by eye whether the twins are monozygous or dizygotic. To determine the zygosity of twins, different methods, starting with an assessment of the external similarity of twins and ending with a biochemical blood test. The most simple

the way to determine zygosity is to compare twins according to a number of traits that are hereditarily given and at the same time do not change under the influence of the environment. These include - eye and hair color, shape of lips, ears, nose and nostrils, fingerprints, etc. When examining a large sample of twins, parents or other experts are asked to fill out a questionnaire about the similarities in the appearance of twins and whether other people confuse twins.

Restrictions the method of twins is associated with possible environmental differences in the perinatal and postnatal development of MZ and DZ of twins, as well as twins and single-born children, to whom the results of the twin study are transferred.

Differences in perinatal development can occur due to unequal blood supply to MZ twins compared to DZ twins. This is due to the fact that MZ twins quite often have one set of amniotic membranes for two, and DZ twins always have separate sets. As a result, the difference in the supply of oxygen and nutrients through the blood leads to a greater difference in the weight of newborn MZ twins compared to DZ twins. In turn, the differences in the perinatal development of twins and single-born children are associated with the fact that in the first case, two children are simultaneously provided with oxygen and nutrients, and in the second case, only one. Therefore, with multiple pregnancies, newborns are, on average, physically less developed than single-born children.

Environmental conditions in postnatal the development of MZ and DZ of twins may also differ. For example, the similarity of MZ twins is often specifically emphasized by parents (children are dressed the same, give them similar names, treat them similarly), which is less typical for DZ twins. MZ twins are more likely than DZ twins to be together, have the same circle of friends, the same hobbies, etc. Such a greater similarity of the environment in pairs of MZ twins, as compared to pairs of DZ twins, can lead to the emergence of additional nongenetic similarity of MZ twins, which contradicts the assumption that the environments in MZ and DZ pairs are equal. Another example: the peculiarities of the environment can increase the differences between the members of both the MH and the DZ couples (the desire to be different from the co-twin, the distribution of roles in the couple, the different relationships of children with their parents). The options for the influence of a specific twin environment on the similarity of both MH and DZ of twins can be very different. In turn, single-born children, in contrast to the MH and DZ of twins, develop outside the specific twin environment, which can have a significant impact on the formation of the psychological characteristics of the child.

Thus, the limitations of the twin method are associated with pre- and postnatal environmental conditions development that can increase or decrease the similarity between members of twin pairs. If the postulate on the equality of environments violated and the common environment makes a different contribution to the similarity of the MZ and DZ of twins according to the studied trait:

1) the intra-pair
the similarity of twins - either MZ, or DZ, or both types
twins;

2) intrapaired similarity of twins of different types can
change as unidirectional (for example, decreases
similarity in pairs and MZ, and DZ twins), and different
directionally (for example, the similarity in pairs of MH and
the similarity in pairs of DZ twins decreases).

To overcome the indicated limitations of the method, it is necessary to assess the sensitivity studied signs to the peculiarities of the twin environment, that is verify the postulate about the equality of the environments of the MH and DZ of twins; and the postulate about the representativeness of the sample of twins to the sample of single-born children. Thus, it is possible to assess the relationship between birth weight and the further psychological development of the child; to determine whether the features of the twin environment of the MH are more similar and whether this affects the level of psychological similarity, for example, in the properties of temperament; check whether there are significant differences in this characteristic between twins and singles, etc.

2.7. Conclusions on the second chapter

Thus, the most accurate assessment of the contribution of heredity and the environment to the formation of individual differences allows the family method, the method of foster children and the method of twins. These methods can be divided into "rigid" and "non-rigid" experimental schemes. The method of foster children and the method of separated twins make it possible to clearly separate the influence of genetic and environmental factors, while the classical version of the method of twins and the family method require additional validation. In the case of the classical twin method, it is necessary to conduct additional research to verify the postulate about the equality of the environments of the MZ and DZ twins. In the case of the family method, in order to increase reliability, distant relatives are compared, who, as a rule, live and are raised in different environmental conditions.

It is worth noting that the family study itself has a very low resolution. But the inclusion of family data in a study of adopted children (comparing adopted children with siblings and step siblings) or in a study of twins (comparing MH and DZ of twins with parents and siblings) allows us to resolve controversial issues in the interpretation of the results. For example, combining the family method with the twin method helps to understand the type of inheritance (additive or non-additive) and to control environmental variables (general and individual environment, the effect of twinning).

If the study uses only one of the psychogenetic methods, it is recommended to compare the data obtained with the results of studies carried out using other methods. This will help to more accurately interpret the results obtained and, ultimately, to more accurately understand the nature of individual differences in the studied psychological or psychophysiological characteristics. As an example, Table 4 shows intelligence data obtained using different methods. It can be seen from this table that the similarity in intelligence monotonically increases as the genetic similarity of the compared people increases.

MOSCOW EXTERNAL HUMANITARIAN UNIVERSITY ACADEMY OF PEDAGOGY FACULTY OF PEDAGOGY DEPARTMENT OF PSYCHOLOGY AND PSYCHOLOGICAL CONSULTING "Methods of psychogenetics" 3 Methods of psychogenetics 4 Method of twins 6 Classical twin method. 9 Control twin method. 10 Longitudinal twin study. 10 Method of twin families. 10 Exploring twins as a couple. 10 Matching twins to non-twins. 10 Separated Twins Method. 11 Partially separated twins method. 12 Genealogical method 13 Population method 17 Method of foster children 18 Conclusion 21 Literature: 22 Psychogenetics Psychogenetics is an interdisciplinary field of knowledge, bordering "between psychology (more precisely, differential psychology) and genetics; the subject of her research is the relative role and action of heredity and environmental factors in the formation of differences in psychological and psychophysiological characteristics.In recent years, the scope of psychogenetic research includes individual development: both the mechanisms of transition from stage to stage, and individual trajectories of development. Russian terminology, it seems inadequate (at least in relation to a person). And here's why. In Russian psychology, the understanding of the term "behavior" has changed, and quite strongly. development ”, and, consequently, the laws established for specific mental functions are valid for it. However, in subsequent years, "behavior" began to be understood more narrowly, rather as a designation of some external forms, external manifestations of human activity, with personal and social motivation. S.L. Rubinstein wrote back in 1946 that just when Motivation moves from the realm, objective, to the sphere of personal-social relations and acquires a leading value in a person's actions, “human activity acquires a new specific aspect. It becomes behavior in the special sense that this word has when people speak in Russian about human behavior. It is fundamentally different from "behavior" as a term in behavioral psychology that is retained in this sense in zoopsychology. Human behavior includes, as a defining moment, the attitude towards moral norms. " BG Ananyev considered the question of the relationship between "behavior" and "activity" in a different aspect, namely from the point of view of which of these two concepts is more general, generic. He believed that his decision could be different depending on the angle of study of a person. The task of psychogenetics is to elucidate not only hereditary, but also environmental reasons for the formation of differences between people according to psychological characteristics. The results of modern psychogenetic studies provide information about the mechanisms of action of the environment to the same, if not more, degree as about the mechanisms of action of the Genotype. In general terms, it can be argued that the main role in the formation of interindividual variability according to psychological characteristics belongs to the individual (unique) environment. Its role is especially high for personality and psychopathological signs. An increasing emphasis in psychogenetic research is placed on the relationship of the socioeconomic level of the family or the length of schooling with the results of testing the intelligence of children. Even such formal characteristics as the parameters of the family configuration (the number of children, the ordinal number of birth, the interval between births) are not indifferent for the individualization of the child - both in the cognitive and personal spheres. As a result, the psychological similarity of the members of the nuclear family found in the study may have both genetic and environmental origins. The same can be said about a decrease in similarity with a decrease in the degree of kinship: as a rule, in this case, we are dealing with different families, i.e. we are talking about reducing not only the number of common genes, but also about the different family environment. This means that a decrease in similarity in pairs of people related by more distant kinship is also not evidence of the genetic determination of the trait under study: in such pairs, the genetic commonality is lower, but at the same time the environmental differences are higher. All this leads to the conclusion that family research by itself, without combining with other methods, has a very low resolution and does not allow to reliably "separate" the genetic and environmental components of the variance of a psychological trait. Although, when combined with other methods, for example, with twin methods, family data makes it possible to solve issues that cannot be solved without them (for example, to clarify the type of inherited transmission - additive or dominant), or to control environmental variables (for example, the family and individual environment, the effect twins). Methods of psychogenetics METHODS OF PSYCHOGENETICS (from the Greek. Psyche-soul, genos-origin) - methods to determine the influence of hereditary factors and the environment on the formation of certain mental characteristics of a person. The twins method is the most informative. It is based on the fact that monozygotic (identical) twins have an identical genotype, dizygotic (fraternal) twins - non-identical; however, members of any type of twin couples should have a similar parenting environment. Then the greater intrapair similarity of monozygotic twins compared to dizygotic twins may indicate the presence of hereditary influences on the variability of the trait under study. A significant limitation of this method is that the similarity of the psychological characteristics of monozygotic twins may have a nongenetic origin. The genealogical method is the study of the similarities between relatives in different generations. This requires accurate knowledge of a number of characteristics of direct maternal and paternal relatives and coverage of the widest possible range of blood relatives; it is also possible to use data on a sufficient number of different families to reveal the similarity of pedigrees. This method is mainly applicable in medical genetics and anthropology. However, the similarity of generations in terms of psychological characteristics can be explained not only by their genetic transmission, but also by social continuity. The population method allows you to study the distribution of individual genes or chromosomal abnormalities in human populations. To analyze the genetic structure of a population, it is necessary to examine a large group of individuals, which must be representative, that is, representative, allowing one to judge the population as a whole. This method is also more informative in the study of various forms of hereditary pathology. As for the analysis of the heritability of normal psychological characteristics, this method, taken in isolation from other methods of psychogenetics, does not provide reliable information, because differences between populations in the distribution of a particular psychological feature can be caused by social reasons, customs, etc. - comparison of the similarity in any psychological characteristic between the child and his biological parents, on the one hand, the child and the adoptive parents who raised him, on the other. Methods involve mandatory statistical processing specific to each method. The most informative methods of mathematical analysis require the simultaneous use of at least the first two methods. Twin Method As is known, most mammals have more than one calf in one litter. This is due to the fact that during ovulation, several eggs mature at the same time. In some animal species and in humans, during ovulation, only one egg usually matures and, therefore, only one baby is born. But there are also exceptions - two or more eggs mature and fertilize at the same time. In this case, two (or more) babies are born, and as they come from different fertilized eggs (zygotes), they are called dizygotic twins (DZ). Moreover, dizygotic twins do not always have one father. If a woman during ovulation had contact with several men, then a situation is possible in which the born DZ will have different fathers. In some cases, when a single mature egg is fertilized at the initial stages of development, the zygote is divided into two parts. This phenomenon leads to the birth of the so-called monozygotic twins (MZ). Since MZ originate from the same zygote, they have the same genetic set, which determines their external similarity. Sometimes the separation of embryos does not occur completely and as a result, the so-called Siamese twins are born. At the birth of twins, four different options for the ratio of the membranes of the fetus are possible:. twins have separate amnions, chorions, and placentas; ... twins have separate amnions, chorions, and a common placenta; ... twins have separate amnions and a common chorion and placenta; ... twins share the amnion, chorion, and placenta. For DZ twins, only the first two types are characteristic; at the birth of MZ twins, all four types of the ratio of the membranes can be observed. The birth rate of twins in different populations is different, but this difference arises mainly due to the difference in the frequency of births of DZ twins, while the frequency of birth of DZ twins in all populations is approximately constant. The number of births of MZ and DZ twins can be approximately determined using a simple method. MZ twins are always same-sex, while DZ twins are born same-sex and bisexual with the same probability. Consequently, the birth rate of DZ twins is equal to twice the birth rate of heterosexual twins. And the birth rate of MZ twins is, respectively, equal to the difference between the birth rate of all twins and the birth rate of DZ twins. Since MZ twins develop from the same zygote, they are genetically identical and all observed differences in phenotypes should be associated only with the influence of the environment. Therefore, at first glance, it seems that in order to determine to what extent the variability of a trait is determined by genetic factors, it is enough to establish the level of similarity of the MZ of twins. This assumption would be true if, from the moment of birth of MZ, the twins were separated and raised in different environments. But in most cases this does not happen and the twins are brought up in the same environment. Therefore, to take into account the influence of the general environment, pairs of DZ twins are used as a control. On DZ twins, the factor of the common environment acts to the same extent as MZ of twins, but the common genes in DZ twins are approximately two times less. Therefore, the level of genetically determined similarity in DZ twins should be lower than that of MZ twins. The twin method was proposed by F. Galton in 1865, but the final development of its foundations was carried out by G. Siemens in 1924. Semens has developed a reliable method for diagnosing zygosity (the method of polysymptomatic comparison), based on assessing the similarities and differences of twins in a number of parameters. Each parameter separately does not allow making judgments about the zygosity of twins, but the use of a set of parameters allows for a more reliable diagnosis. In addition, he suggested using not only MZ twins, but also DZ twins as an object of research. The principles laid down by G. Siemens in the basis of the twin method have not undergone any significant changes until now. The twin method in the classic version is based on several assumptions. ... First, it is assumed that the environments for partners are equal both in pairs of MZ and pairs of DZ twins. In this case, if the variability of a trait is completely determined by the environment, then both the MZ and DZ twins should have equally high intra-pair correlations for this feature, close to 1.0. If the variability of a trait depends entirely on the genotype, then the correlation coefficient in the group of DZ twins should be close to 1.0, and in the group of DZ twins it is approximately equal to 0.5 (i.e., the degree of relationship of DZ twins, the similarity of their genotype). ... Second, it is assumed that there is no systematic difference between twins and singles. Otherwise, the results of twin studies cannot be transferred to the general population. There should also be no systematic differences between the types of twins themselves. The principle of assessing the role of the environment and genotype according to the data obtained by the twin method is clear from Fig. 1. In the upper part of Fig. 1 shows the factors that are not recorded in the twin experiment (common environment, different environment, covariance of genotype and environment, experimental error). The genotype and the common and different environment are latent (implicit) variables not directly measurable during the experiment. The lower part of the figure shows the parameters directly measured during the experiment (intelligence indicators, reaction speed, etc. of the first and second twins). Lines represent the effect of latent variables on the studied characteristics. As can be seen from the figure, the correlation between the members of the MH and DZ pairs can be determined by the genotype and the general environment. If the general environment is the same for the members of the MH and DZ of twin pairs, then a comparison of the intra-pair similarity of the MH and DZ of twins allows one to obtain information about the role of the genotype and the environment in the variability of the studied characteristic. If the provision on the equality of environmental conditions for the development of MH and DZ of twins is not observed, then the estimates of the components of phenotypic variance (heritability, variance of the effects of the common and different environments) are distorted. Such distortion can occur in a number of cases:. Environmental conditions can increase the intrapair similarity of the MZ of twins. Emphasizing similarities by others can lead to the appearance of additional (non-genetic) similarities between members of the MH of a pair of twins. This contradicts the accepted assumption about the equality of common environments for MZ and DZ pairs, since for DZ pairs such an emphasis on similarity is less typical. In the case of studying a sign that is weakly dependent on the specific features of the environment (for example, psychophysiological characteristics), the error will be small. But if a trait is sensitive to this kind of features of the twin environment, then the twin method is of little use for its study, since the principle of equality of environments is violated and the common environment will make a greater contribution to the similarity of MZ twins than to the similarity of DZ twins. ... Environmental conditions can reduce the intrapair similarity of DZ twins. Thus, a number of studies have shown that the environmental conditions of development tend to increase the differences in the DZ of twins: parents tend to emphasize the differences in DZ of twins (for example, success in different types of activity); the twins themselves tend to emphasize their dissimilarity. This leads to the effect of dissimilation - a gradual difference between the DZ of the twins. If the studied psychological characteristic is formed with the participation of environmental factors contributing to dissimilation, then the heritability indicator will be overestimated, as in the first case, since the common environment will make a smaller contribution to the similarity of DZ twins than to the similarity of MZ twins. ... Development conditions can equally reduce the similarity of partners of both MH and DZ couples. Some of them are associated with the period of intrauterine development and childbirth, some fall on the subsequent stages of development. During fetal development, twins often find themselves in unequal conditions. So, all nutrients and oxygen enter the fetus through the placenta. All DZ twins and about one third of MZ twins have separate chorions and placentas. The remaining two-thirds of MZ twins have a common chorion and placenta. In this case, in the fetal membranes of the so-called monochorionic twins, various connections (shunts) are formed between the vascular systems of the twins. In the case of the formation of an arteriovenous shunt, the artery of one twin is connected to the vein of the other. In this case, one of the twins may not get enough oxygen-rich and nutrient-rich arterial blood, the possible excess of both in the second twin may also not contribute to normal development. Fortunately, usually there are several shunts of approximately equal power, which cancel each other out. If the compensation is insufficient, then one of the twins develops in conditions of oxygen and nutrient deficiency. In this case, there is a significant difference between twins at birth, primarily in weight. A similar difference can be observed in DZ twins and dichorionic MZ twins due to uneven compression of the placentas during multiple pregnancies. The stage of labor can also cause strong environmental differences for twins. The twin who is born first has a greater chance of getting a birth injury. At the same time, the second twin most often occupies the wrong position in the uterus, which leads to the need for artificial obstetrics. In addition, the second twin spends longer in childbirth and, accordingly, experiences oxygen deprivation for longer and more acutely, which negatively affects the development of the nervous system. Environmental differences between twins also arise at subsequent stages of development, even when brought up in the same family. This is most often due to the bias of parents towards each of the twins, while the physical characteristics that have arisen at the stage of intrauterine development and childbirth are aggravated. Also often there is a division of responsibilities between twins (the case of a complementary relationship), separation of couples on the principle of "leader - follower". Thus, if environmental conditions have a different effect on the formation of the studied characteristic in MZ and DZ twins, then the heritability indicator of this characteristic may be distorted: underestimated if the common environment makes a smaller contribution to the similarity of MZ twins than to the similarity of DZ twins; overestimated - in the opposite case. The twin method has a number of varieties. The classic twin method. In this case, such an experimental scheme is used, in which the severity of the studied trait is compared in pairs of MZ and DZ of twins and the level of intrapair similarity of partners is assessed. Control twin method. This method is used on samples of MH twins. Since MZ twins are very similar in many ways, it is possible to make two samples from the partners of MZ pairs, equalized by a large number of parameters. Such samples are used to study the influence of specific environmental influences on the variability of a trait. In this case, the selected part of the twins (one from each pair) is exposed to a specific effect, while the other part is the control group. Since genetically identical people participate in the experiment, this method can be considered a model for studying the impact of various environmental factors on the same person. Longitudinal twin study. In this case, long-term observation of the same twin pairs is carried out. In fact, this is a combination of the classic twin method with the longitudinal one. It is widely used to study the influence of environmental and genetic factors in development. Twin family method. It is a combination of the family and twin methods. At the same time, family members of adult twin couples are examined. According to the genetic constitution, the children of the MH twins are, as it were, the children of one person. The method is widely used in the study of hereditary causes of a number of diseases. Study of twins as a couple. It involves the study of specific twin effects and the characteristics of intra-pair relationships. It is used as an auxiliary method to test the validity of the hypothesis about the equality of environmental conditions for the partners of the MH and DZ pairs. Matching twins to non-twins. Also an auxiliary method to assess the significance of the difference between twins and non-twins. If the difference between twins and other people is not significant, then twins and other people belong to the same general sample and, therefore, the results of twin studies can be generalized to the entire population. So it was noted some lag in the development of members of twin couples from single-born. This difference is especially noticeable at an early age. But comparing the results of the study of members of twin couples whose partner died in early childhood and singles did not reveal a significant difference in the level of development. That is, the peculiarities of the development of twins are caused not so much by the difficulties of embryonic development, but by the peculiarities of raising twins as a couple (family difficulties in giving birth to twins, the isolation of twins in a couple, etc.). Thus, the twins are somewhat different from the entire population, but with age this difference is noticeably smoothed out and the twins for the most part become comparable with the rest of the population. Separated Twins Method. Due to the peculiarities of the development of DZ and MZ pairs of twins, the classical twin method and its varieties are considered to be “non-rigid” experiments: it is impossible to unambiguously separate the influence of genetic and environmental factors in them, since, for a number of reasons, the conditions for the development of twins turn out to be incomparable for a number of reasons. Therefore, the experiments carried out according to the above schemes require additional verification. It can be of two types. Firstly, it is possible to test the hypothesis about the similarity of the environment of MZ and DZ of twins, that is, to prove that the studied characteristic is not affected by differences in the environment of MZ and DZ of twins. But such a check is very difficult and has low reliability. Secondly, the research data can be compared with the results of research on "hard" schemes, which allow you to accurately separate the influence of environmental factors from genetic ones. One of these methods is the separated twins method. This method makes an intra-paired comparison of twins separated at an early age. If MZ twins were separated in a similar way and grew up in different conditions, then all their similarities should be determined by their genetic identity, and the differences - by the influence of environmental factors (see figure). Monozygotic twins Dizygotic twins Genetic and environmental factors that determine the similarity of separated twins. Partially separated twins method. This method consists in comparing the intrapair similarity of the MZ and DZ of twins living separately for some time. In these studies, it is also possible to determine to what extent the postulate of the equality of the environments of the MZ and DZ of twins is valid. So, if MZ twins living separately become less and less similar to each other in some psychological characteristic, and DZ twins living apart do not differ in intra-pair similarity from DZ twins living together, then we can conclude that the environmental conditions of MZ and DZ are unequal. and conclusions about the heritability of the studied characteristic overestimate the indicator of the heritability of this characteristic. Genealogical method The genealogical method consists in studying genealogies based on Mendelean laws of inheritance and helps to establish the character of inheritance of a trait (dominant or recessive). This is how the inheritance of individual characteristics of a person is established: facial features, height, blood type, mental and mental makeup, as well as some diseases. For example, when studying the genealogy of the royal dynasty of the Habsburgs, a protruding lower lip and a humped nose can be traced for several generations. This method revealed the harmful consequences of closely related marriages, which are especially manifested in homozygosity for the same unfavorable recessive allele. In related marriages, the probability of having children with hereditary diseases and early infant mortality is tens and even hundreds of times higher than the average. The genealogical method is most often used in the genetics of mental illness. Its essence consists in tracing the manifestations of pathological signs in the genealogy using the methods of clinical examination, indicating the type of kinship between family members. This method is used to establish the type of inheritance of a disease or a separate trait, to determine the location of genes on chromosomes, to assess the risk of manifestation of mental pathology in medical and genetic counseling. In the genealogical method, 2 stages can be distinguished - the stage of compiling genealogy and the stage of using genealogical data for genetic analysis. Compilation of a pedigree begins with the person who was examined first, he is called a proband. Usually this is a patient or an individual who has manifestations of the studied trait (but this is not necessary). The pedigree should contain brief information about each member of the family, indicating his relationship to the proband. The pedigree is represented graphically using standard notation, as shown in Fig. 16. Generations are indicated in Roman numerals from top to bottom and put them to the left of the pedigree. Arabic numerals denote individuals of the same generation sequentially from left to right, while brothers and sisters or siblings, as they are called in genetics, are arranged in the order of their date of birth. All members of the genealogy of one generation are located strictly in one row and have their own code (for example, III-2). According to the data on the manifestation of the disease or some studied property in the members of the pedigree, using special methods of genetic and mathematical analysis, the problem of establishing the hereditary nature of the disease is solved. If it is established that the studied pathology is of a genetic nature, then at the next stage the problem of establishing the type of inheritance is solved. It should be noted that the type of inheritance is established not one by one, but by a group of pedigrees. A detailed description of the pedigree is important for assessing the risk of manifestation of pathology in a particular member of a particular family, i.e. when conducting medical and genetic counseling. When studying the differences between individuals on any basis, the question arises about the causal factors of such differences. Therefore, in the genetics of mental illness, a method for assessing the relative contribution of genetic and environmental factors to interindividual differences in susceptibility to a particular disease is widely used. This method is based on the assumption that the phenotypic (observed) value of a trait in each individual is the result of the influence of the individual's genotype and those environmental conditions in which it develops. However, it is almost impossible to determine this in a specific person. Therefore, appropriate generalized indicators are introduced for all people, which then make it possible to determine, on average, the ratio of genetic and environmental influences on an individual. A genealogical study of the families of persons suffering from mental illness has convincingly shown the accumulation of cases of psychosis and personality anomalies in them. An increase in the incidence of the disease among close relatives was found for patients with schizophrenia, manic-depressive psychosis, epilepsy, and some forms of oligophrenia. The summarized data are given in the table. | Disease | Parents | Brothers, sisters | Children | Uncles, aunts | | proband | | | | | | Schizophrenia | 14 | 15-16 | 10-12 | 5-6 | | Manic- | 16 | 18 | 18-20 | 8-10 | | depressive | | | | | | psychosis | | | | | | Epilepsy | 12 | 14 | 8-10 | 4-5 | Risk of illness for relatives of mentally ill patients (in percent) It is important to take into account the clinical form of the illness in genetic analysis. In particular, the frequency of schizophrenia among relatives largely depends on the clinical form of the disease that the proband suffers from. The table contains data reflecting this pattern: | Affinity | Continuous | Seizure-Warming | Recurrent | | | | dietary | | | | Schizophrenia | Abnormalities | Schizophrenia | Abnormalities | Schizophrenia | Abnormalities | | | | character | | character | | character | | Grandparents | 1.3 | 20.6 | 2.5 | 14.7 | 1.4 | 19.1 | | | | | | | | | | Aunts-uncles | 2.5 | 10.8 | 6.7 | 7.1 | 3.0 | 11.6 | | | | | | | | | | Parents | 6.7 | 76.0 | 17.4 | 50.6 | 18.0 | 28.6 | | Sisters-bra | 18.7 | 15.7 | 10.6 | 21.4 | 19.4 | 16.6 | | thya | | | | | | | | Children | - | - | - | - | 26.3 | 13.2 | The risk values given in the tables allow the doctor to navigate in the inheritance of the disease. For example, the presence of another sick relative in the family (besides the proband himself) increases the risk for the rest of the family, and not only when both or one parent are sick, but also when other relatives (siblings, aunts, uncles, etc.) are sick. ). Thus, close relatives of people with mental illness are at increased risk for a similar illness. In practice, it is possible to distinguish: a) high-risk groups - children, one of whose parents is sick with a mental illness, as well as siblings (brothers, sisters), dizygotic twins and parents of patients; b) groups of the highest risk - children of two sick parents and monozygotic twins, one of whom got sick. Early diagnosis, timely qualified psychiatric care are the essence of preventive measures in relation to this contingent. The results of clinical genetic studies form the basis of medical genetic counseling in psychiatry. Medical genetic counseling can be schematically reduced to the following stages:. establishing the correct diagnosis for the proband; ... drawing up a genealogy and studying the mental state of relatives (for a correct diagnostic assessment in this case, the completeness of information about the mental state of family members is especially important); ... determination of risk by disease based on data; ... assessment of the degree of risk in terms of "high - low". Risk data are communicated in a form appropriate to the needs, intentions and mental state of the consultant. The doctor must not only communicate the degree of risk, but also help to correctly assess the information received, weighing all the pros and cons. It is also necessary to eliminate in the consultant the feeling of guilt for the transmission of the predisposition to the disease; ... formation of an action plan. The doctor helps in choosing this or that decision (only the spouses themselves can have children or refuse to bear children); ... follow-up. Observing the family seeking counseling can provide the clinician with new information that can help clarify the risk. Population method The terms "gene pool" and "genogeography" belong to population genetics. As a science of the genetic processes occurring in the population of any kind of organisms and of the diversity of genes, genotypes and phenotypes of the population generated by these processes, population genetics dates back to 1908, with the formulation of the first genetic principle, now known as the Hardy-Weinberg principle of genetic equilibrium. It is significant that the genetic processes occurring in human populations, in particular one of their specific manifestations - the stable preservation in many generations of the frequency of such a mendelating trait as brachydactyly, served as an incentive to formulate the principle of genetic equilibrium, which is of universal significance for populations of any species of bisexual organisms. ... This method is aimed at studying the inheritance of mental disorders in families of patients by comparing the frequency of the corresponding pathology in these families and among population groups living in similar natural and climatic conditions. Such groups of people in genetics are called populations. In this case, not only geographic, but also economic, social and other living conditions are taken into account. The genetic characteristics of populations allows us to establish their gene pool, factors and patterns that determine its preservation and change from generation to generation, which is achieved by studying the characteristics of the spread of mental diseases in different populations, which, in addition, provides the possibility of predicting the prevalence of these diseases in subsequent generations. Genetic characterization of a population begins with an estimate of the prevalence of the disease or trait under study in the population. These data are used to determine the frequencies of genes and corresponding genotypes in the population. Method of adopted children The first work carried out using this method was published in 1924. The results, from the author's point of view, indicate that the intelligence of adopted children depends more on the social status of biological parents than adopted ones. However, as noted by R. Plomin and co-authors, this work had a number of defects: only 35% of the 910 children surveyed were adopted before the age of 5; the measurement of mental abilities was carried out on a rather rough (three-point in total) scale. The presence of such flaws makes it difficult to analyze the study meaningfully. 25 years later, in 1949, the first work appeared, made according to the complete scheme of the method. It was followed by others, the largest of which were two modern programs: the Texas and Colorado foster child research projects. Now, despite some criticism (we will talk about it later), the method of foster children is theoretically the purest method of psychogenetics, with the maximum resolving power. Its logic is simple: as early as possible, adoptive parents, their biological and adoptive parents, are included in the study. With the former, children have, as I degree relatives, on average 50% of common genes, but do not have any common environment; with the latter, on the contrary, they have a common environment, but do not have common genes. Then, when assessing the similarity of the studied trait in pairs [child-biological parent] and [child-adoptive parent], we should get the following picture: a greater proportion of genetic determinants will manifest itself in a greater similarity of the child with his biological parent; if environmental influences prevail, then, on the contrary, the child will be more like an adoptive parent. This is the basic version of the method. The similarity between biological parents and their children given up for foster care provides a fairly reliable characterization of heritability; the similarity of adopted children with adoptive parents assesses the environmental component of the variance. For control, it is desirable to include in the study ordinary families - parents and children living together. One of the very interesting and informative variants of the method is the study of the so-called composite siblings, i.e. several unrelated children adopted by the same family. Given that such children do not have common genes, their similarity (if found) can only be the result of the action of the general family environment. There are two schemes of this method: full and partial. The first involves combining data from two groups of separated relatives (biological parents and their children given to adoptive parents; separated siblings) and adopted siblings; comparing - either one or the other group of data. In the first case, R. Plomin and his coauthors write, there are “genetic” parents (parents and their abandoned children), “environment” parents (adoptive parents with their adopted children), and as a control - the executive group “genetic plus environmental” parents (biological a family). Comparison of these three groups makes it possible to reliably "separate" the factors that form family similarity. " A necessary condition for the use of the method of adoptive children is a wide range (preferably representative) of environmental conditions in adoptive families, on the contrary, equalization of these families according to certain characteristics (for example, according to the high intelligence of adoptive parents or educational styles) with the subsequent comparison of the individual characteristics of those adopted by them. children from biological parents who had polar values of the studied trait .; for example, it has been shown that, firstly, children of biological parents with low intelligence, who are in a good environment, have intelligence significantly higher than that which could be predicted, but, secondly, in an equally good environment of adoptive families, the distribution of intelligence ratings adopted children significantly depends on the intelligence of biological parents; if they had high (> 120) IQ scores), 44% of children have the same high intelligence and no one has a grade below 95; if the parents had an IQ of 120 points. In other words, in an equally good environment, the distribution of IQ scores of foster children is shifted towards high values if biological parents had high intelligence, and towards low values - if they had reduced intelligence. (Results of this kind prompted a witty remark from one of the psychogeneticists: "It is best to assume that intelligence is 100% dependent on genes and 100% on the environment.") There are several problems with possible limitations of the method. First, how representative of the population is the group of women that give birth to children? But it is controllable. For example, in the largest program, the Colorado Study of Foster Children, all participants (245 biological parents, their abandoned children and adoptive parents, as well as 245 control families with biological and adoptive siblings) were representative of the general population in terms of cognitive characteristics, personality traits, and family environment. , educational and social economic status. The authors note that even if by some parameters the samples turn out to be deviating from the population distributions, this should be taken into account when interpreting the results, but does not give a reason to consider the method invalid. Secondly, a more specific question arises about the selectivity of placing children in foster families: are there any similarities between siblings and foster parents in some way? It is clear that such similarity will overestimate the correlation in pairs [child x adoptive parent], if the studied trait is determined by heredity, and in pairs [child-biological parent], if it is more determined by the environment. In any case, estimates of the genetic or environmental component of the variability of a given trait will be distorted. Thirdly, there is the problem of prenatal influences of the maternal organism on the characteristics of the unborn child, which should increase the similarity between the mother and the given child due to intrauterine, but environmental, and not genetic factors. According to some researchers, by the time of birth, the human fetus already has some "experience", because its neuroanatomical features, cortical substrate and structure of the intrauterine environment allow for the possibility of some "learning". If this is the case, then the similarity of the biological mother to the given child may have a non-genetic origin. As a result, some researchers even believe that the method of foster children is very informative for studying various postnatal environmental influences, but not for solving the genotype-environment problem. However, according to R. Plomin and his co-authors, comparison of correlations in pairs [given child-biological mother] and [child-biological father] can serve as a good control. It is clear that in the latter case, intrauterine non-genetic influences are excluded. There are also more subtle circumstances that are important for the assessment. For example, the possibility of the formation of subjective legends about adoptive parents in a situation where the child knows that he is not in a given family. In experimental work, this creates a hindrance, since such a legend may turn out to be a rather serious educational factor. Some studies have shown that in the same family, foster siblings have an external locus of control, while biological children have an internal one, which obviously indicates differences in the process of their socialization and leads to the formation of differing personality traits. In our country, it is impossible to use this method, since we have a legally guaranteed secret of adoption. This is a humane, pedagogically absolutely correct, in our opinion, decision, but it means that the researcher has no right to seek information about foster children, especially about their biological parents. Thus, the existing ideas about the limitations and conditions of using the method of foster children are described, reasoned, and for the most part can be either controlled or taken into account when interpreting the results obtained. Therefore, it is one of the main methods of modern psychogenetics. Conclusion Psychogenetics, in contrast to conventional psychotherapy, gives very reliable results without tying the patient to the doctor. One of the main provisions of psychogenetics is that our brain is a supercomputer programmed by heredity and our individual consciousness. There is a genetic code that determines the appearance, psychological traits of a person's character and his fate. Alcohol abuse, criminal behavior, and other social behaviors tend to be rooted in genetic predisposition. A person, having understood his genetic code, working on himself, achieves success himself. An important prerequisite for success is the ability to make decisions. We all do this on a daily basis, but remember that a decision will not be a decision until you act on it. Important decisions such as getting married or investing money can be unsuccessful. The reason is simple: we have not learned (or have not been taught) to defend, making, our decisions and believe in them. Our spirit is almost always positive. He says: "I can," but he can lead to success only if the consciousness does not contradict him. The body has to obey the instructions of consciousness and act accordingly. Action needs a motive, a reason that gives meaning to the action. Therefore, it is imperative that we make decisions and act in the direction we want. Don't belittle your dignity. When you do this, you are telling your consciousness, "I am bad," or "I am a failure." Thus, you subconsciously tune in to even greater setbacks. But, actually, what is success? Someone considers himself lucky, having held out at work for six months, another thinks that he was lucky if the day passed without quarrels with his wife. Success is very relative and depends entirely on how unlucky you feel. Since our consciousness agrees with who you are and what you think of yourself, focus on the fact that you are doing great. Think back to your great deal last week instead of dwelling on today's troubles. After all, every experience, every effort you make is an important stepping stone to achieving your goal. Consider yourself lucky! Literature: 1. Ayala F., Keiger J. Modern genetics: In 3 volumes. Moscow: Mir, 1987 2. Malykh SB, Egorova MS, Meshkova TA. Fundamentals of psychogenetics. M .: Epidaurus, 1998 3. Martsinkovskaya ETC. History of Psychology: Textbook. manual for stud. higher. study. institutions.- M .: Publishing Center "Academy", 2001 4. Moskalenko VD, Shakhmatova IV, Gindilis VM Medical genetic counseling in schizophrenia (guidelines). - M .: Ministry of Health of the USSR, 1981 5. Ravich-Scherbo IV, Maryutina TM, Grigorenko EL. Psychogenetics: Uch. for universities. M .: Aspect Press, 1999 6. The role of the environment and heredity in the formation of human individuality / Ed. I.V. Ravich-Scherbo. M .: Pedagogy, 1988