A person, are they born or made? What is more important in shaping their personality, biology or education? For centuries, this debate has divided the scientific community and society as well. Curiosity, ambition, responsibility, or kindness seem like traits that are shaped throughout a lifetime. However, science already knows that personality has a genetic component thanks to a very simple trick: comparing identical twins with fraternal twins. If the former resemble each other more in their way of being than the latter, it is because some of it is in the DNA. What was not known was where that something was. A large-scale study published this Wednesday in Nature by an international consortium of researchers offers, for the first time, an answer: they have found 1,260 distinct genetic variants, 824 of them never before linked to personality, spread throughout the genome.
Read more A judge summons Begoña Gómez to testify after a complaint by Vito Quiles for false accusation
The work analyzes data from 1.14 million people, organized into 46 groups, to track which DNA variants are associated with the five major personality traits already identified by scientific literature (Big Five): extraversion, kindness, responsibility, neuroticism, and openness to experience. The results do not suggest that personality can be directly predicted from DNA; rather, they indicate that some variants may influence some behaviors. And they confirm that, in any case, education and social life continue to weigh more on personality than genetics.
The international consortium of researchers who conducted this pioneering study has found those 1,260 genetic variants associated “in a statistically robust way,” they say, with personality. This represents a leap of between 3 and 43 times compared to previous studies, depending on the trait. Combined, these variants explain between 4.8% and 9.3% of the variation of each trait among people. This is a figure much lower than the 40%-60% indicated by classic twin studies. This means that the environment has a decisive weight in how personality is shaped.
However, and curiously, the family is less relevant than one might imagine. Unlike other social traits (such as educational level, income, intelligence), personality is barely determined by the family environment. When researchers compared siblings with each other or children with their parents, the genetic effects remained practically identical to those observed in the general population. “It is one of the things that surprised me the most,” admits Michel Nivard, professor of Genetic Epidemiology at the University of Bristol and one of the main authors of the study. “At the educational level, we see a clear correlation between the genes that influence education and the environments that favor it: children of parents with more education inherit certain alleles, but they also go to better schools because their parents have more resources and invest in them. For personality, that effect almost does not exist,” he explains.
Another important result of this work is that there is nothing like a “personality gene.” Unlike diseases such as Alzheimer’s, where certain variants drastically multiply the risk, each of the 1,260 identified variants provides a microscopic push: the average effect of the most influential one, on extraversion, is equivalent to the difference between being at the 50th percentile of the population and the 50.35th, a tiny nuance. The authors insist that not even by adding hundreds of thousands of these variants can the personality of a specific individual be reliably predicted; these indices are only useful when averaging large population groups. Nivard sums it up like this: “If you want to know your personality, the easiest thing is to take a twenty-minute test [which you can consult here]: the reliability is very high, and if you repeat it a year later, you will get almost the same result.” The researcher, therefore, does not believe that a genetic test that determines the personality you will have can ever exist.
Responsibility is associated with less smoking
The study does not stop at the genome but crosses those variants with dozens of real behaviors. Some results are striking. People with more variants linked to openness to experience tend to move, already in middle age, to urban and cosmopolitan neighborhoods; those who score higher in responsibility move to affluent residential areas. Openness is associated with more nighttime activity, and responsibility with more daytime activity. Responsibility is associated with less smoking and a lower body mass index.
Read more The Andalusian left demands Moreno to take in migrant minors from Ceuta
Of the five traits that mark personality, kindness is the most problematic to analyze: researchers have found fewer genetic correlations between countries and also that it is a less heritable trait. Nivard offers a possible explanation: “kind” may not mean the same everywhere. “I am Dutch, and we are very direct. In other cultures, that same frankness could be perceived as a lack of kindness,” he reasons. It is, he explains, the first time genetics allows objectively checking if two cultures are measuring the same thing when using the same word.
Another result contradicts much of the previous research: genetic profiles associated with openness to experience correlate with a higher risk of psychopathology in general, something that previous clinical studies had not detected so clearly. Nivard does not have a closed theory: “It is fascinating, but I don’t know what it means yet.” He considers as a possible explanation that people open to new experiences participate more in this type of study, even suffering from some disorder, which could slightly bias the sample. It is a hypothesis that, he warns, remains to be verified.
Because the great finding of this study, in reality, is not what is published today, but all that remains to be published. The work has such an amount of data (one million people organized into 46 research groups, or cohorts, offers many possibilities to cross data) that its analysis will surely mark the evolution of genetics, sociology, psychology, and psychiatry. And it is only the tip of the iceberg: the human genome has between four and five million genetic variants, which opens the door to further research. For geneticist Miguel Pita, who did not participate in the study, the merit is not so much in the result (“that genetics matters a lot in personality is almost obvious,” he says) as in having demonstrated it with this enormous amount of data: “It is a milestone in experimental and technical design. Sometimes, the obvious is the hardest to prove.”
The study insists that the old question of “nature or nurture” no longer makes sense to pose as a dilemma. Nivard resorts to a comparison: in a genetic study on lung cancer, the variant most associated with the disease is in the nicotine receptor gene, although no one disputes that smoking is the cause, and it is environmental. According to Pita, “in everything related to personality, both factors will always play a role; talking about only one or the other is an outdated debate.” Nivard agrees and believes that continuing to oppose genes and environment is “old-fashioned, although it is logical that many people still find it intuitive: it is what we learned in high school.”
Read more Justice will auction a Ferrari seized from Aldama in the ‘hydrocarbons case’ for 241,000 euros
