Researchers at Hebrew University in Jerusalem say that they have discovered that a gene called AVPR1a is linked with ruthlessness, and that it may explain the money-grabbing tendencies of those with a Machiavellian streak. Lead researcher Richard Ebstein revealed that the genetic link was established through an economic exercise called the 'Dictator Game', in which more than 200 student volunteers participated. The exercise allowed the participants to behave selflessly, or like money-grabbing dictators like former Zaire President Mobutu who filled in his pockets at the cost of its citizens.
Ebstein said that, while the exact mechanism by which the gene influences behaviour was unknown, one could say that one some people just did not believe in the old adage that "it is better to give than to receive". He indicated that there the reward centres in their brains might derive less pleasure from altruistic acts leading them to behave more selfishly.
The researchers specifically focused on AVPR1a as it is known to produce receptors in the brain that detect vasopressin, a hormone involved in altruism and 'prosocial' behaviour. They wondered if differences in expression of this receptor in the human brain might make different people more or less likely to behave generously.
During the study, the researchers tested DNA samples from the participants before asking them to play the dictator game. The students were divided into two groups: 'dictators' and 'receivers' (called 'A' and 'B' to the participants). Each dictator was told that they would receive 50 shekels (about 14 US dollars), but were free to share as much or as little of this with a receiver, whom they would never have to meet. The receiver's fortunes thus depended entirely on the dictator's generosity.
The scientists observed that almost 18 per cent of the dictators kept all of the money, nearly one-third split the money down the middle, and a generous six percent gave it all away. While no link was found for this tendency to be gender-specific, but it was dependent on the length of the AVPR1a gene, as people having the shorter version of this gene were more likely to behave selfishly.
Ebstein said that the vasopressin receptors in the brains of people with short AVPR1a might be distributed in such a way that it makes them less likely to feel rewarded by the act of giving. Based on his observations, Ebstein came to the conclusion that the dictatorial tendencies certainly had a genetic component.
However, Nicholas Bardsley at the University of Southampton, UK, who studied the Dictator Game, said that researchers should be careful while using such games as a tool for arriving at results regarding human generosity. The study has been reported in the journal Genes, Brain and Behavior 1.