Scientists talked about the connection of genes with the social behavior of children

The same child may be willing to help loved ones at home, but experience difficulties in relationships with classmates. When studying the genetics of social behavior, such differences are important: the connections between genetic variants and behavior vary depending on age, situation, and who evaluates the child. This conclusion was reached by an international group of scientists who analyzed the data of more than 73 thousand people. About how the study was conducted and why its results do not allow predicting the character of an individual child, see the "Izvestia" material.

What exactly did the scientists study

Social behavior consists of different actions and attitudes. In the study, the authors identified two areas. The first is prosocial behavior: willingness to help, share, and comfort others. Scientists were interested in differences in the severity of these qualities, including cases when such behavior is less frequent. The second area is difficulties in communicating with peers and other people, for example, difficulties in establishing friendly relationships.

These indicators cannot be reduced to a single characteristic like "sociability". A child may rarely share toys and still easily make friends. The opposite situation also happens: the desire to help others is combined with difficulties in relationships with peers. In addition, behavior changes as you get older, and at home and at school it manifests itself in different circumstances.

The authors of the paper, published in the journal Nature Human Behavior, combined information from 25 research cohorts. The analysis included 73,321 people and 491,246 assessments of their social behavior. Many participants were evaluated repeatedly; the age range covered ranged from two to 29 years old. Behavioral data came from parents, teachers, and the participants themselves. The main genetic analysis was carried out on samples of people of European origin.

Questionnaires, including standardized ones, were used to assess behavior in different cohorts. The researchers had to compare questions from different methodologies in order to combine the results. They then examined how the associations of individual genetic variants with behavior differed between the two behavioral domains, ages, and observer groups.

Experts explained the influence of the parent's phone on the child's psyche

Why is it important who describes the child's behavior?

Parents, teachers, and the children themselves see different sides of the same life. A parent observes communication in the family, a teacher observes relationships in the classroom, and a teenager can talk about experiences and friendships that are not obvious to adults. Therefore, a discrepancy between the answers does not necessarily mean that someone made a mistake.

In most large-scale genetic studies, information from different sources is combined to obtain an overall assessment of the trait being studied. The authors of the new work used a method that allows for separate consideration of age, area of behavior, and who reported it. This is how they tested whether the genetic link persists during the transition from one situation and group of observers to another.

At the same time, the "social context" in the article has a well-defined meaning: it is about the type of behavior being measured, the age and the source of the assessment. The study does not prove that a child's transition from home to school alone changes the effect of a particular gene. It shows that genetic connections look different depending on which behavior is being studied, when, and through whose eyes.

What genetic connections were found?

Scientists have identified six regions of the genome associated with the studied indicators of social behavior. For all six, the strength of the connection varied depending on the area of behavior, age, or source of assessment. The most pronounced signal was located inside the CADM2 gene and related to a low level of prosocial behavior, which the participants themselves reported in late childhood and early adolescence. CADM2 is involved in organizing connections between nerve cells; other variants in this gene have previously been linked, in particular, to autism.

"Finding" a connection to a part of the genome does not mean finding a "gene for kindness," a "gene for friendship," or a reason for a certain behavior. Each identified variant is associated with only a small part of the observed differences. In addition, a statistical relationship by itself does not prove that a variant directly causes a particular behavior feature.

In a broader analysis, common genetic variants were associated with about 2-7% of the differences in the studied measures of social behavior. This is an assessment for groups of participants within the framework of the applied method. It does not mean that a particular person's behavior is "2-7% determined by genes," and it does not cover all possible genetic influences. The authors also described four interrelated genetic factors: two reflected differences between the studied areas of behavior, and two more reflected the characteristics of parents' and teachers' assessments.

According to senior researcher Beate Saint-Pourcin, children grow up in different social worlds — at home and at school — where different behaviors are required of them. It also changes with age. Therefore, she explained, genomic studies should take these differences into account, rather than reducing all observations to one general assessment.

Attention to the screen: parents change communication with children to video content

Gadgets interfere with speech development and inhibit the formation of neural connections

What did the additional check show?

To test how useful context accounting is, the researchers compiled polygenic estimates. Unlike the analysis of a single DNA region, such an indicator combines information about a variety of genetic variants, each of which makes a small contribution to the statistical relationship with the trait under study.

Polygenic assessments were tested on independent samples of a total of 16,305 people of European and African descent. The results were better consistent with the observed behavior when the social context coincided during the construction and verification of the assessment, that is, comparable behavior indicators and conditions for their assessment were taken into account. The authors also reported that some of the results were reproduced in samples of a different origin, but this does not remove restrictions on transferring conclusions between populations.

The researchers compared the genetic links of social behavior with data on other signs and conditions, including autism and attention deficit hyperactivity disorder. The connections appeared at different stages of development, depending on which area of behavior and which source of assessment were considered. This helps to study the general patterns of development, but it does not mean that the peculiarities of a child's communication make it possible to diagnose or determine in advance whether he will develop any condition.

Why can't DNA predict a child's behavior?

The authors separately warn against using the results for individual forecasts. The genetic connections found are too small to determine by the presence or absence of a variant what a child will be like, how he will become friends or whether he will help others.

Behavior is influenced by family, peer relationships, cultural norms, communication opportunities, personal experiences, and other circumstances. These factors can interact with each other and with genetic characteristics. The article also notes that the very idea of expected social behavior depends on the society in which the research is conducted. Since the main samples consisted mainly of people of European descent who grew up in modern Western societies, the conclusions cannot be automatically transferred to other cultural and genetic groups.

The importance of the work lies primarily in the approach to the study of development: the assessment of behavior becomes more accurate when researchers distinguish its forms and take into account age and the observer. In the future, the team plans to separately study possible differences in genetic connections between men and women.