We’ve all heard phrases like “he’s got his father’s bad temper,” “he’s as nice as his mother,” “his grandfather was as mean as a child,” and others like that.
Therefore, as it seems that our way of being is something that comes from the family, to what extent is personality inherited? What is most important to define it: genes or the environment? How do you know? Let’s see below.
What is the relationship between genetics and behavior?
Like most animals, humans inherit DNA from our parents, half of which is maternal DNA and the other half is paternal DNA. This genetic inheritance influences various aspects, including our behavior, our character and our values.. However, and this is the point that differentiates us from animals, is that we are able to set goals and have aspirations, which can be fostered by the environment, family and cultural, that we have to live. .
Another difference that sets us apart from other animals is that humans are aware of our genetic inheritance – that is, how similar we are to our parents, both psychologically and physically, and resorting to free will. , we can try to move away. of what’s supposed to be in our genes. It is a field of study of behavioral genetics.
Although it is known that the behavioral aspects, both those which are adaptive and those which involve psychopathology, are more or less hereditary. a misconception before the development of the human genome project was that every behavior or aspect of personality and intelligence would be delimited by one or a small group of genes.. However, research revealed that there were no genes for, for example, schizophrenia, giftedness or the extraversion dimension.
Each of these aspects, and virtually all of human behavior, depends on the interaction of several genes, which can be counted in the thousands. Each gene has minimal impact on personality, but together they shape it and resemble that of the parents.
Nothing against the environment: who will win?
The influence of genes and environmental factors on an individual’s behavior is highly variable throughout life. We have seen that families, which are in themselves an environmental factor, have a preponderant influence on the cognitive capacities of a child during his earliest childhood. However, when these children have grown up and are already of primary school age, it seems that the genes have taken over, blocking environmental influences.
Obviously, the claim that six-year-olds are a pure heirloom and nothing of environmental influence is not wrong. Education in school, as well as contact with other children and the experience of what types of events, benign or adverse, shape their way of being and their knowledge, however, it is in these years that their genetic code seems more relevant in determining personality.
Indeed, between three and six years old, children try to find an environment that suits them, that is to say, they select friendships according to their way of being. try to create an environment that matches your predispositions. For example, a child who tends to be more active will surely be interested in sports, which will motivate him to play football in the schoolyard and have contact with other children who enjoy the activity.
Is the personality inherited?
The personality heritability approach has been carried out through the best type of study that behavioral geneticists have been able to do: studies of twins, both with monozygotes or genetically identical, and with dizygotes or dizygotes. twins. These experiences are ideal, especially when identical twins have been separated at birth.. These traits they share, despite having been raised in different households, will be attributed to genetic factors.
Although this type of research continues to pose some methodological problems, there are certain trends in the results. Because the most powerful personality model today is that of the Five Factors (Big Five) of McCrae and Costa, in which the personality is defined on the basis of five major dimensions: extraversion, cordiality, neuroticism, openness to experience. and accountability. .
Studies that have investigated the personality of twins, both identical and fraternal, indicate that there is a strong heritability of traits, especially monozygotic twins. That means if, for example, an identical twin is friendly, the other twin, with high security, is also friendly. This is a clear indication that the personality is strongly influenced by genetic inheritance.
How does genetics influence it?
When it is said that something is encoded in genes and is the product of inheritance, it is referring to the concept of heritability of a given 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 variation in traits, such as being creative, plays a major role in genes, while a low heritability indicates that environmental factors are more important.
Research suggests that the heritability of personality traits is around 40-50%. This means that about half of the variation in personality can be attributed to a genetic component.
This should not be misinterpreted, as it does not mean that half of an individual’s personality is due to genetic factors. Unshared environmental factors would account for about 30% of the variation and shared factors 20%.
What should be clear about the concept of personality heritability is that it does not indicate that we have about a 50% chance of inheriting the personality from our parents or that we will share 50% of it. . Heritability data indicate that, for example, if one person is creative and another less, much of this difference is due to genetics and the rest is due to having received influences from the environment, both shared and unshared.
Heritability should not be confused with the idea of genetic determination. The latter refers to the fact that genes can determine a particular trait, as long as one knows which gene or genes are involved in that determination.
So, when analyzing to what extent a particular personality trait is hereditary through genes, it should be borne in mind that we are not analyzing the probabilities of receiving that characteristic from paternal or maternal DNA, but that this is an estimate of a relative nature, based on comparisons between individuals, and which focuses on variation.
Also, keep in mind that in many ways, 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 virtually everyone had more or less religiosity, and it is only recently that it has been seen as a phenomenon closely related to cultural dynamics.
Likewise, the influence of genetics on personality is not studied from the idea that a certain way of behaving is “natural” and is present to varying degrees in everyone due to genetic aspects, but which takes into account that genes and experience are constantly interacting, even where they don’t seem to.
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