Is the personality inherited? This is how genes influence us

We have all heard expressions like "she has the bad temper of her father", "she is as kind as her mother", "her grandfather was also naughty as a child" and many others like that.

That is why, based on the fact that it seems that our way of being is something that runs in the family, To what extent is personality inherited? What is more important when defining it: genes or environment? How do you know? Let's see it next.

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Genetics and behavior, what relationship do they have?

As with most animals, human beings inherit DNA from our parents, which is made up of half the maternal DNA and the other half the paternal DNA. This genetic inheritance influences several aspects, including our behavior, character and values.. However, and this is the point that differentiates us from animals, is that we are capable of proposing goals and have aspirations, which can be promoted by the environment, family and culture, that touched us to live.

Another difference that differentiates us from other animals is that humans are aware of our genetic inheritance, that is, to what extent we are so similar to our parents, both psychologically and physically, and, using free will, we can try to move away from what is supposed to be in our genes. This is the field of study of behavioral genetics.

Although it is known that behavioral aspects, both those that are adaptive and those that involve psychopathology, are to a greater or lesser extent heritable, a mistaken belief before the development of the Human Genome Project was that each behavior or aspect of personality and intelligence would be delimited by one or a reduced group of genes. However, the research found that there was no single gene for, say, schizophrenia, giftedness, or the extraversion dimension.

Each of these aspects, and practically all of human behavior, depends on the interaction of several genes, which can number in the thousands. Each gene has a miniscule impact on the personality, but collectively they shape it and resemble that of the parents.

Genes versus environment: who will win?

The influence of genes and environmental factors on an individual's behavior is highly variable throughout life. It has been seen that families, who are themselves an environmental factor, have a prominent influence on the cognitive abilities of the child during his earliest childhood. Nevertheless, When these children are old enough to go to elementary school, it seems that genes take over, blocking the influences of the environment.

Obviously, the claim that six-year-olds are pure heredity and no environmental influence is false. Education at school, together with contact with other children and the experience of depending on what type of events, benign or unfavorable, shape his way of being and his knowledge, however, it is in these years that his genetic code seems to be more relevant when determining his personality.

In fact, between the ages of three and six, children try to find an environment that suits them, that is, they select friendships based on their way of being, they try to create an environment that is consistent with their predispositions. For example, a child with a tendency to be more active may be interested in sports, which It will motivate you to play soccer in the schoolyard and have contact with other children who enjoy this activity.

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Is the personality inherited?

The approach to the heritability of personality has been carried out through the best type of study that geneticists of the behavior could have achieved: studies of twins, both with monozygotic or genetically identical, and with dizygotic or twins. These experiments are ideal, especially when identical twins have been separated at birth.. Those traits they share, despite having grown up in different homes, will be attributed to genetic factors.

Although this type of research continues to have some methodological problems, there are certain patterns in the results. As the most powerful personality model today is McCrae and Costa's Big Five, in which defines personality based on five major dimensions: extraversion, cordiality, neuroticism, openness to experience and responsibility.

Studies that have studied the personality of twins, both identical and fraternal, indicate that there is a high heritability of traits, especially being monozygotic twins. This means that if, for example, an identical twin is cordial, the other twin, with high security, is also cordial. This is a clear indication that personality is greatly influenced by genetic inheritance.

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To what extent does genetics influence?

When it is said that something is encoded in the genes and is the product of heredity, mention is made of the concept of heritability of a certain trait. Heritability indicates what percentage of variation in the traits of two individuals is due to genetic causes. A high percentage of heritability indicates that the variation of the trait, say for example being creative, has a large prominence genes, while a low heritability means that environmental factors have greater importance.

Research indicates that the heritability of personality traits is around 40% -50%. This means that about half of the personality variation can be attributed to a genetic component.

This should not be misinterpreted, since it does not mean that half of an individual's personality is due to genetic factors. The environmental factors not shared would explain about 30% of the variation, and the shared ones 20%.

What should be clear about the concept of heritability of personality is that it does not indicate that we have close to a 50% chance of inheriting the personality of our parents, or that we will share 50% of that personality. The heritability data indicates that, for example, if one person is creative and another is less so, much of that difference is due to genetics and the rest is due to having received influences from the environment, both shared and non-shared.

Heritability should not be confused with the idea of ​​genetic determination. The latter refers to the fact that genes can determine a specific trait, as long as the gene or genes involved in such determination are known.

Thus, when analyzing the extent to which a certain personality trait is heritable through genes, one must take into account in mind that we are not analyzing the probabilities of receiving this characteristic from the paternal or maternal DNA, but what it is a relative estimate, based on comparisons between individuals, and that focuses on variation.

In addition, it must be borne in mind that in many respects, cultural phenomena are so ubiquitous that they can easily be mistaken for something determined by genetics. For example, the degree of religiosity of people: for centuries, practically everything in the world presented religiosity to a greater or lesser degree, and only in recent times has it been seen that it is a phenomenon closely linked to cultural dynamics.

In the same way, the influence of genetics on personality is not studied from the idea that a certain way of behaving is "natural" and is present in different degrees in all people due to genetic aspects, but it is taken into account that genes and experience are constantly interacting, even where they are not. It seems.

Bibliographic references:

• Church, A. T. (2000). Culture and Personality: Toward an Integrated Cultural Trait Psychology. Journal of Personality, 68 (4): pp. 651 - 703.
• Harris, J.R. (nineteen ninety five). Where is the child's environment? A group socialization theory of development. Psychological Review, 102 (3): pp. 458 - 489.
• Jang, K., Livesley, W.J., & Vernon, P.A. (nineteen ninety six). Heritability of the big five personality dimensions and their facets: a twin study. Journal of personality, 64 (3): pp. 577 - 591.
• Vukasović, T., & Bratko, D. (2015). Heritability of personality: A meta-analysis of behavior genetic studies. Psychological Bulletin, 141 (4), 769–785. https://doi.org/10.1037/bul0000017
• Strobel, Maria; Tumasjan, Andranik; Spörrle, M. (2011). Be yourself, believe in yourself, and be happy: Self-efficacy as a mediator between personality factors and subjective well-being. Scandinavian Journal of Psychology, 52 (1): pp. 43 - 48.