Is our personality determined by our genes?

In Zelig (1983), Woody Allen tells the story of a man who lacks personality. Throughout the film, Leonard Zelig takes on the behaviour of those he knows and admires. So much would be more or less normal, as we all imitate those we like. However Zelig amazes us because he copies everything: gestures, phrases, attitudes, opinions, dress… He ends up adopting the identity of a vampire and then suddenly behaves like an orthodox Jew, an African-American street musician or a high-handed intellectual psychiatrist. He wants to be everyone, and in the end he is nobody. His sad history embodies an idea very present in the modern world: the need for personality.

Although it is a psychological phenomenon that is difficult to define, coherence in the way of being is so indispensable that we notice its absence when it is not present. Therefore, when someone in our environment acts randomly, adapting to the circumstances and to the expectations of others, we say that he/she lacks a missing personality. And when a person exhibits a consistent pattern of behaviour, for example, being resolute and self-confident in his or her family and work life, we refer to him or her as a person with a strong personality.

German psychoanalyst Erich Fromm said that the main task of man in life is to give birth to himself, to become what he potentially is. And the modern world repeats phrases about the need to be oneself. This current prioritization of personal coherence is a product, according to psychologist Roy Baumeister, of several historical milestones. For this researcher from Florida State University, the revolutionary social changes of the last few centuries have led us to put our personal identity before the pressure of others and the circumstances we live in. Now, for example, we know each other better and, according to this author, this is partly due to the general practice of confession, introduced by Catholicism. 

Our identity is individual 

The changes in our way of defining ourselves have also been important: from the 17th century, identity is individual and no longer associated with family lineage. Our relationship with society has also changed: romantic rebelliousness is one of the factors that increased the perception that it is healthy to be in conflict with the world in order to maintain our identity. Finally, the need for self-realization from our personal style since the rise of capitalism is being greatly encouraged.

All these factors cited by Baumeister lead us to attach great importance to our personality. If you ask those around you, you’ll see that they all think they have a certain consistency of behavior and self-define by character traits. We believe to be stubborn or flexible, sincere or Machiavellian, sociable or shy But are we like that or is it just the image we have of ourselves? Are there personality traits that remain stable throughout life? Or was the 16th century French essayist Michel de Montaigne right when he said that there is as much difference between us and ourselves as there is between us and the others?

But if our interpretation of circumstances tells us that it is better to act differently, we will behave differently without any problems. It is a theory that does not postulate permanent personality traits: we only seem consistent in our behavior because we often reach the same conclusions in similar environments. But as soon as we change habitat, for example, when we change our circle of friends, our significant other or country of residence, we act differently.

German psychoanalyst Erich Fromm said that the main task of man in life is to give birth to himself, to become what he potentially is. And the modern world repeats phrases about the need to be oneself. This current prioritization of personal coherence is a product, according to psychologist Roy Baumeister, of several historical milestones. For this researcher from Florida State University, the revolutionary social changes of the last few centuries have led us to put our personal identity before the pressure of others and the circumstances we live in. Now, for example, we know each other better and, according to this author, this is partly due to the general practice of confession, introduced by Catholicism. 

Our identity is individual 

The changes in our way of defining ourselves have also been important: from the 17th century, identity is individual and no longer associated with family lineage. Our relationship with society has also changed: romantic rebelliousness is one of the factors that increased the perception that it is healthy to be in conflict with the world in order to maintain our identity. Finally, the need for self-realization from our personal style since the rise of capitalism is being greatly encouraged.

All these factors cited by Baumeister lead us to attach great importance to our personality. If you ask those around you, you’ll see that they all think they have a certain consistency of behavior and self-define by character traits. We believe to be stubborn or flexible, sincere or Machiavellian, sociable or shy But are we like that or is it just the image we have of ourselves? Are there personality traits that remain stable throughout life? Or was the 16th century French essayist Michel de Montaigne right when he said that there is as much difference between us and ourselves as there is between us and the others?

But if our interpretation of circumstances tells us that it is better to act differently, we will behave differently without any problems. It is a theory that does not postulate permanent personality traits: we only seem consistent in our behavior because we often reach the same conclusions in similar environments. But as soon as we change habitat, for example, when we change our circle of friends, our significant other or country of residence, we act differently.

Current criticisms of personality tests are moving in that direction. Thus, psychologist Adam Grant of the University of Pennsylvania has recently published research with which he wants to show that the Myers-Briggs indicator, one of the most used, lacks scientific reliability. The characteristics measured by this test have hardly any predictive power about whether we will be happy in a situation, how we will perform in our work or what our marriage will be like, says this researcher.

The theory of traits 

The opposite approach, the one that believes that there is a constancy in our actions that can be catalogued by test, would be represented above all by the theory of features, based on factorial analysis. These experts say that there is statistical evidence that certain kinds of attitudes usually occur together, and that shows that there is a personality characteristic that encompasses them all.

For example, the British psychologist Hans Eysenck, the best known advocate of this technique, found that the tendency to feel better in the face than in large groups, the need to experience moments of solitude every little time, the propensity to read or listen to music in silence and to be likely to have few but very good friends are related.

This group of characteristics was called introversion, one of the personality traits of which we will speak in this article. His argument is not based on the constancy that we perceive in others or in ourselves, but on the fact that there are personality variables that are reflected mathematically and therefore have a scientific basis.

In fact, Eysenck believed that certain personality traits have a genetic basis. In the case of introverts, they are people, he suggests, who have a higher than usual level of normal brain excitation. This higher level of cortical excitation causes your brain to be continuously active with little need for external stimuli and to focus more on inner thoughts and feelings. The images obtained by PET (positron emission tomography) show that an area of the frontal lobe included in the behavior inhibition is more active in them. And this makes them less spontaneous. Their brain is in continuous activation, and so they regulate the entry of external stimuli.

Studies on the inheritance of personality are highly topical. One example is the research just published by an international group of scientists. The authors [including experts from the University of Granada and Robert Cloninger, One of the most influential psychologists in this field claims to have identified more than seven hundred genes that determine the inheritance of our behaviour.

In the paper, published in the journal Molecular Psychiatry, they defend the theory that the weight of inheritance in the main traits of our personality ranges between 30% and 60%. Until now, according to these researchers, there were no great advances in the detection of the mechanisms that model it because previous work focused on the effect of individual genes. However, this new research uses artificial intelligence techniques to find clusters of genes that interact with each other and the environment, and try to analyse physiological inheritance in all its complexity.

There are intermediate positions between these latter hypotheses based on genetics and those that postulate that personality variables do not exist. Without ignoring human incoherence, they admit that it is important to know our tendencies to behave in a similar way. This is the case, for example, of the theories of the American scientist Seymour Epstein, who argues that our propensities exist, even if they do not determine us so rigidly.Identifying them does not serve, as Mischel reminded us, to predict all our behaviours, but an average.

According to Epstein, one factor against this self-knowledge is the limitations of the tests. As this psychologist reminded us in one of his articles, The advancement of psychology as a cumulative and integrative science is limited not so much by its conceptual complexity as by the difficulty of humans to observe themselves with objectivity, courage and desire to avoid illusions."

One of the problems with the questionnaires is that they are based on what the person tells us about himself, with all the biases that this implies. To be based on the idea that we know what we are, and to differentiate it from what we would like to be, is debatable. 

Psychologist David Funder, for example, raises a hypothesis that would question this belief. According to this professor at Stanford University, the data that would be provided by those who know us would provide more reliable information, because they have seen us act in different contexts thousands of times and they look at us in a slightly more objective way.

Yet many psychologists claim that understanding our personality trends can be a good environmental health variable. It helps us, in the first place, to respect our way of being in situations where we feel different from the majority of those around us. Secondly, to speak of personality variables as propensities to a certain behaviour can serve us to look for vital architectures, work environments, lifestyles, couples, etc.to promote our best potentials. A clear example is the "aperture" dimension to the experience, researched by psychologists such as the American Marvin Zuckerman.

In order to learn about our personality trends, we are going to expose scientific discoveries about some of the variables most used in his study.

Impulsivity vs. Reflexivity 

It is one of the personality variables that, with one or the other name, appear in almost all tests. People who are more prone to being impulsive tend to prioritise action over thought, are resolute in decision-making, and squander much life force. They speak, on many occasions, before thinking about what they are going to say and can act without reflecting on the consequences of their actions. Unpredictability is usually their greatest advantage, because it makes them stand out from the rest.

On the other side would be thoughtful individuals. They tend to think a lot about what they are going to say and value the pros and cons before acting. Thanks to that, they generate a lot of confidence in those around them. In addition, by creating habits of life and customs in which they feel comfortable, they keep decisions for quite some time.

As with other personality labels, proponents of this permanent trait claim that there are biological bases for these vital predilections. The causes of this greater or lesser propensity for self-control seem to lie largely in neurological issues. The most cited physiological correlate is the number of connections between the amygdala, the place where the need for security is created and the cerebral cortex, the part of the brain in which the decision-making process arises.

Those with highly interconnected areas often think hard about what they do, as the amygdala exercises great authority over their actions. Conversely, people with few amygdala-cortex connections tend to ignore precautions and act more spontaneously.

But that’s not the only neurological basis cited. Neuroscientist Hugh Garavan of Trinity College Dublin, supports the hypothesis that there is a correlation between this personality variable and the development of the areas of the brain, fundamentally the frontal lobe and the right region which affect memory.

This would explain that being thoughtful has to do with remembering what happened in other similar situations. Whether or not to suppress an attack of anger depends on memory: we control ourselves because we remember that it went wrong expressing it or we are spontaneous because we forget the negative consequences.

According to Garavan, a sample of the biological basis of this personality variable is adolescent behaviour. At that time, we were all more impulsive. And that coincides with the frontal lobe being the last part of the brain that matures: it does not complete its complete formation until it is 20 years old. At the same time, this is an example of behaviour variable in which research has found effects of environmental influence.

Transcultural psychology, which studies the influence of the type of society in which we have grown in our way of being, has brought several discoveries. Psychologists Hazel Rose Markus of Stanford University and Shinobu Kitayama of Kyoto University conducted research a few years ago that shows that cultures encourage or discourage disinhibition. In societies such as Japan, its members are taught to control their impulses from an early age. Vehemence comes at a high price, and social pressure leads people to learn to be more thoughtful.

On the contrary, other cultures, such as the Maghreb cultures, are much more spontaneous: the one who is excessively cerebral is suspected and the members of these societies develop a greater impulsivity.

Neuroticism vs. emotional stability 

This is another of the personality variables that have appeared in many classifications of human beings. In general, neuroticism has been defined as the tendency to get angry often, lack of tolerance to frustration and difficulty in coping with disappointments caused by other people or by life circumstances. Those at that extreme refuse to resign themselves to life not being as they would like it.

At the other extreme would be the stable ones: they are less rigid and better accept circumstances that go beyond what is planned. They adapt better to the ups and downs of life, have a better mood and seem calm in the midst of very different circumstances. Once again, the authors who most believe in this variable as a fixed personality trait find a biological basis.

Eysenck postulates that neurotics have low threshold excitation of the sympathetic nervous system { this is activated by any minimal vital inconvenience{ which causes them an increase in heart rate and blood pressure}, increased muscle tension, …sweating and the need to put them in order and eliminate the stimulus that has decentralised them. The problem with this variable is that one of the poles seems to have too many negative connotations.

In all questionnaires neuroticism is associated with adherence to the norm, to lack of tolerance to uncertainty… And from there, high scores are associated at this end of the scale with many mental health problems. Psychologist David Watson, a professor at the University of Notre Dame, has compiled research that links neuroticism with ailments such as anxiety disorders, depression, substance abuse, feeding problems and schizophrenia.

The anguish it produces is so high that Watson maintains the hypothesis that this variable, generalised anxiety disorder and major depression are genetically indistinguishable. And he postulates that, more than a personality factor, what has been measured is vulnerability to subjective distress and negative emotionality. 

Introversion vs. extroversion

Do you need to isolate yourself often so as not to have the feeling of helplessness in the crowd, or do you often prefer the company of others? What level of stimulation do you prefer: you feel good in environments with loud music and many people or you almost always choose silence and talks from you to you? These are the kinds of questions that define this personality pattern.

Introverted people are more comfortable in environments with a low degree of external activation. They dose the stimulus: they continuously search for spaces of intimacy and set the life around their need for punctual isolation.For the same reason, they are more selective in their relationships and not easily open to others. A common phenomenon in them is that they usually enjoy more when they remember the good times in company than when they are living them. They are more likely to read or listen to music without dancing to it...

Extroverts, on the other hand, like to be with many people, engage in continuous conversations and have lots of stimuli around them. They can be alone if necessary or if they feel stunned by the situation, but, even in those moments, their mental current is channelled out: they usually play music, turn on the radio or television to keep it as a background sound or listen to messages on their phone continuously. They are more likely to tell everyone about their intimacies and are usually more spontaneous in manifesting their emotions. It is also common for them to have more partners throughout their lives.

The difference between them is one of the most classical divisions in psychology. It appears in all the theories of personality, from that of Eysenck to that of the five great "patterns of study" which examines openness to new experiences, responsibility, extroversion, kindness and neuroticism, and is measured with the most popular tests (MMPI, Myers-Briggs, 16PF, etc.).

These two forms of behaviour have been much talked about lately thanks to what has come to be called the Quiet Revolution. University of Florida professor Jenn Granneman, one of its promoters, reminds us in her book The Secret Lives of Introverts that many of the attitudes associated with introversion are perfectly adaptive. Not providing information on negative aspects of oneself, concentrating in silence and deepening in nutritional relationships rather than scattering time to anyone or being oblivious to group pressure are attitudes that yield good results in many life situations.

Another scientist involved in this silent movement, the American psychologist Susan Cain, speaks in her books and lectures of the need to vindicate the most silent. According to the author of The Power of Introverts, we have been living for decades in a world that encourages extroversion as the healthy pole of this personality variable.

The advocacy of youth and the primacy of social skills over effectiveness seems to be more important to sell our skills than to have them attached to the collective imagination to assume that it is not good to be introverted. The advice of the social counsellors, as teachers, coaches and pedagogues, is directed in recent decades to the subjects to continually manifest their feelings, learn to work with all kinds of individuals without choosing their partners and be able to talk about any subject with anyone. That is why scientists like them analyse what are the vital advantages of both ends to balance the scales.