You’ve probably heard the term “wood shavings” when referring to a son or daughter who looks like his father or his mother. Interest in the scientific study of the effect of heredity on human behavior began with Charles Darwin and his work in the mid-19th century. The origin of species (1859).
However, personality development depends on many factors that are not just related to genes. For example, the American psychologist Albert Bandura (1925-2021) already demonstrated in the 1960s a strong environmental component in behavior, conditioned by imitation from models and reference individuals.
Although a problem that has been overcome for many, the dilemma between genes and environment continues to spark debate. However, this is a false dilemma, as there are data that reflect the weight of heredity and studies that emphasize the weight of environment. The really important thing is to find out what the genetic mechanism is and how the environmental influences work.
Human development seems to depend on the bidirectional relationship established between biological complexity and psychological organization. This includes not only genetic and neurological activity, but also interactions with the environment and with lived experience.
In this way, a person’s relationship to his environment (physical and social) can determine the direction of his development right from his mother’s womb. In fact, prenatal development will depend on the interaction between the mother and the environment. Later, as a person grows, their brain forms new neural connections based on their experiences.
the atmosphere weighs, and much more
The reality is that it is not 100% known if the relationship between our value system and our psychological characteristics, such as intelligence, personality and behavior, is determined by our genetic heritage and how much has to do with the culture, what we have learned. The social and temporal context that surrounds and shapes us.
Australian researcher Nathan Gillespie put the importance of the weight of heredity in the personality of humans at 60%, although he placed great importance on environmental factors. On the one hand, there is the shared environment, that is to say all that we absorb from our family life and that people have in common. and not shared, on the other hand, derived from personal experiences, culture and environment.
Therefore, the genes that parents share with their sons and daughters are not necessarily much more similar than those of two strangers, as the environment will determine that.
Even genetically identical twin brothers display very different personalities. Specifically, when their character traits were scored by tests, they showed about 40% coincidences. Among strangers, this percentage of similarity is not very low: it is around 33%.
If we take into account the fact that each parent shares 50% of the genetic material with its offspring, against 100% for the twins, we would realize the relative weight of the paternal and maternal heritage in the character. This is what differentiates us between some individuals and others.
Inheritance is not a hard fate
However, other studies with twins have shown that certain personality traits are moderately inherited and can predict a variety of lifelong behaviors, including certain mental disorders.
However, the fact that strong heredity may exist does not mean that it cannot be modified by experience. This environmental impact must be studied taking into account the characteristics of the organism (individual considered as a unified whole) and of the context, which are not experienced in the same way by all sons and daughters.
Adopters with a family history of psychosis and those who grew up in a dysfunctional adoptive home environment also have an increased risk of developing a mental spectrum disorder.
Conversely, boys and girls who grew up in families with an atmosphere of respect, responsibility, and love, with consistent rules and boundaries, showed greater emotional well-being. It promotes optimal psychological development in the future and plays a protective role in the manifestation of future mental disorders.
Faced with this scenario, more holistic or comprehensive explanatory models of human development have emerged. Epigenetics fits into this context, which studies how environmental conditions can activate or deactivate the expression of certain genes without altering the genetic sequence.
This will help to understand how the presence of harmful habits during pregnancy is related to a higher risk of suffering from chronic diseases in the offspring. Or, as if it were a memory, the habits of our lives influence and lead generations to come.
Studies of the Great Chinese Famine, the so-called hunger winter The conditions of prisoners of the Dutch war or the Secession or the American Civil war showed that the experience of these episodes left changes in the expression of certain genes – associated with aging and schizophrenia – and affecting the current generations.
Today, epigenetics plays a fundamental role in the interpretation and treatment of many diseases and mental disorders.
Therefore, the term “chips like wood” does not seem generalizable. Genetics and epigenetic factors are crucial to understanding human behavior and mental health, but the environment is a very important variable. Moreover, we must keep in mind that these external factors will not affect all people in the same way.