Genetics and behavior: do genes decide how we act?

The body of human beings is the result of million years of evolution of the material that we find in the nucleus of cells: DNA. Genes are the units of information that this genetic material possesses, and the translation of the genetic code is expressed in characteristics, both physical (the color of the eyes, the type of hair or the shape of the nose) and psychological (the behavior or the personality).

But does it all depend solely on genes? Namely, Are we what we are and do we behave as we do because our DNA says that we are? The answer is no. The environment around us has something to say about it. Human nature is very complicated, but we are getting closer to understanding it every day.

Genetically based behavior

Using twins for studies has been a great tool that scientists have used for years to understand how genes and the environment influence each person differently. The idea is to look at the extent to which it is upbringing or genes that serve to better predict the regularities that can be found in the development of the organism and the repertoire of behaviors usual.

Twin research shows strong evidence for when and how genes and the environment shape human nature. Some of them reveal that the importance of genes can change drastically depending on the stage of life in which we find ourselves. Genetic influence tends to increase over the years in many characteristicsYes, as seen with body weight.

In another area, twin research has been important in the field of molecular genetics. The best known is with body weight. Thanks to this kind of study, it has been possible to identify almost 100 genetic variants implicated in obesity.

But the effect of genes does not have to be limited only to how our body is formed; it also explains how certain psychological predispositions appear. For example, it is believed that we make choices in search of an environment that favors our predisposition to express genetically inherited strengths. A teenager who is genetically good at reading will probably start going to a library looking of more books, there he will meet people who think similar to him and may begin to relate to they.

In the same way, the IQ is largely heritable and it is difficult to modify it in a meaningful and sustained way through exercises and new learning.

The fear of genetic determinism

Twin studies are a great opportunity to understand when the environment has the most force on us and when behavior is easier to shape.

However, in the field of psychology and cognitive sciences, they have been involved in the controversy. Critics of twin research question that psychological characteristics, such as mental health, have a strong genetic basis. This is due in part to a fear of the idea that everything we think, feel and do is little more than the consequence of genes doing their job and condemning us to a life we ​​cannot change.

However, this fear is unfounded.

Genes aren't everything

The influence that genetics has on human characteristics is often misinterpreted. It is wrong to assume that a behavior that has a strong genetic influence must be innate out of obligation. Genes are not everything; a gene will be expressed depending on the environment, that is, it can show its effects or directly have none, depending on the environment in which we live.

With an example it will be clearer. There are people who are predisposed to lung cancer due to their genetics. Unless they constantly smoke or breathe tobacco smoke, it is very likely that they will not develop the disease. And the same is being seen with behavior. The behavior is obtained as a response to an environmental signal.

Although some forms of behavior have a genetic basis, this does not imply that this predisposition will make Our brain is designed so that we manifest these behaviors regardless of the way we interact with the environment. Although our DNA cannot be modified through experiences and learning, the expression or not of its genes depends largely on the environmental conditions in which we live. For example, studies in relation to schizophrenia (a mental illness with a strongly inheritable component through genes) show that the expression of the disease is greater when one lives in a context that produces stress.

Does knowing the genetic basis imply danger?

One of the fears generated from these studies is that, by recognizing that behavior has a genetic basis, the people will no longer be equally responsible for engaging in healthy behaviors and educating their children.

However, knowing one's own predisposition to suffer a mental or other type of illness does not have to lead to a loss of interest in improving health, on the contrary, you gain a commitment and motivation to change your behavior and habits.