Friday, April 18, 2008

The "Dictator" Gene?

Advances in genetics are helping us gain a better understanding of the role genes play in different, complex behavioral traits and characteristics.

And the latest issue of the journal Genes, Brain and Behavior has this article which nicely illustrates the kinds of insights being made. The lengthy title is "Individual differences in allocation of funds in the dictator game associated with length of the arginine vasopressin 1a receptor RS3 promoter region and correlation between RS3 length and hippocampal mRNA" by Knafo A et. al. Naturenews has a story about the study's findings here.

The study suggests that there is a genetic link to "ruthlessness", which is tested in an economic exercise called the "Dictator Game". Here is an excerpt from the Naturenews story:

Ebstein and his colleagues decided to look at AVPR1a because it is known to produce receptors in the brain that detect vasopressin, a hormone involved in altruism and 'prosocial' behaviour. Studies of prairie voles have previously shown that this hormone is important for binding together these rodents' tight-knit social groups.

Ebstein's team wondered whether differences in how this receptor is expressed in the human brain may make different people more or less likely to behave generously.

To find out, they tested DNA samples from more than 200 student volunteers, before asking the students to play the dictator game (volunteers were not told the name of the game, lest it influence their behaviour). 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 (worth about US$14), 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.

About 18% of all dictators kept all of the money, Ebstein and his colleagues report in the journal Genes, Brain and Behavior. About one-third split the money down the middle, and a generous 6% gave the whole lot away.

....There was no connection between the participants' gender and their behaviour, the team reports. But there was a link to the length of the AVPR1a gene: people were more likely to behave selfishly the shorter their version of this gene.

....Though the mechanism is unclear, Ebstein says, he is fairly sure that selfish, greedy dictatorship has a genetic component. It would be easier to confirm this if history's infamous dictators conveniently had living identical twins, he says, so we could see if they were just as ruthless as each other.