2 min read
Some years ago, I received a video of a class reunion that I could not attend. While watching it I was struck by the amazing extent to which personality traits had been preserved from childhood to adulthood. Those who had been introverted as children stood apart and alone at the reunion, looking a bit out of place in the socially intense event taking place around them. Those who had laughed often as children laughed just as often as adults; the loud kids had become loud adults; and the handful who had been prone to anti-social violence as children did not show up at all.
Anyone who experiences such a reunion cannot fail to come away with the strong feeling that major elements of personalities are determined in the first few years of our lives. In fact, in recent years an increasing number of scientific studies have revealed that our personalities are fashioned even earlier than that - not in the first few years after birth but in the nine months preceding it. The linkage between genes and various diseases, including psychiatric diseases, is of little surprise to most of us. But new genetic research is uncovering insights into what determines personalities. New discoveries are exposing the tight connection between specific personality traits and genetic profiles. These include risk-taking, parental warmth, empathy, leadership, infidelity, stress, aggression, and more.
For instance, papers edited by Peter Hatemi and Rose McDermott, and published by the University of Chicago Press in 2011, suggest we vote for Tories or Labour depending partially on our genetic profile.
Ariel Knafo, of the Hebrew University, and his associates published a paper on the genetic basis of generosity. They investigated a gene known to be responsible for secreting vasopressin, a hormone that generates mother-child bonding. Shorter versions of the gene, which tend to create smaller amounts of vasopressin, are more common among individuals suffering from autism. Knafo and his colleagues studied hundreds of healthy subjects and categorised them according to the length of the gene that each one carried. They then had these subjects play a simple donation game: players were divided into pairs. One was selected to receive a sum of money and was given an opportunity to donate some of it to the other player. Subjects carrying shorter versions of the gene donated much less than those with longer versions.
In spite of these startling findings it is rarely the case that a trait is affected by a single gene; it almost always involves many of them. But, more importantly, while our personality is affected by our genes it is never determined by them. Who we are is a result of a complex interaction between our genes, our environment, and our life experiences.
So how do we know whether a certain trait is influenced by genes and to what extent? A recent survey paper in Wiley Online Library by Richard Ebstein from the National University of Singapore use studies of twins to estimate the heredity component in a variety of traits. Heredity has the greatest influence on pro-social behaviour (helping, donating, and co-operating). Genes are responsible for more than half of these traits. Other traits that come out high on the heredity scale are empathy, political orientation, male stress and female infidelity. Heredity has least influence on trust and trustworthiness.
There is cause for concern, given the potential implications of current and future genetic research. This concern should never allow us to restrict scientific progress but it will require governments to impose more restrictions on its usage. If genes can reveal something about our personality, we can expect that our genetic information will be valuable for others. Recruiters might decide a saliva test to assess genes is as important as a CV. Those with "attractive" DNA profiles will get the best jobs, those with "ugly" profiles will be left behind. Within a few years, this sort of discrimination could in itself strengthen the impression that a person's DNA profile categorically determines his or her chances of success in life. Social mobility would slow to a trickle, as a new genetic aristocracy emerges.
Eyal Winter is the author of 'Feeling Smart' (Public Affairs, £17.99)