Comment »Posted on Thursday 7 May 2009 at 12:07 pm by Jacob Aron
In Biology, Getting It Wrong

Long time readers of Just A Theory will be well aware of my hatred of a well-worn science journalism trope, the “formula for” story. This vile being has a sibling which I’m surprised to realise I’ve never written about: the “gene for” story. In a way this variety of nonsense is much more dangerous, allowing people to blame their genetic makeup for their faults and vices.

A perfect example of this is a recent story in The Telegraph: “Why risk taking runs in the family – scientists find gene that makes you gamble“. The gist is scientists at University College London have discovered that people with the “short” version of a particular gene are more likely to take a gamble than those with the “long” version. In fact, that’s not what they found at all.

Suppose we play a game. I offer you £50, and a choice. You can either keep £20, and give the rest back to me, or you can take a gamble with a 40% chance of winning the whole £50, and a 60% chance of losing everything. If you don’t like that game, we can play a different one. This time I offer you £50, but if you don’t take the gamble you lose £30.

The two games are actually the same, but just framed differently. “Keep £20″ is the the “gain frame” whilst “Lose £30″ is the “loss frame”. The researchers at UCL were investigating the way this “frame effect” can influence the decision making process. Previous research suggests that the amygdala, an area of the brain involved in processing emotions, shows activity when making decisions involving the frame effect. This new research demonstrated that variation in the serotonin transporter gene, which is thought to influence the amygdala, can also influence frame effect decisions.

Thirty participants were split into two groups, those with the “short” and those with the “long” version of the gene, and both groups played a number of games like those described above. Despite being aware that the “gain” and “loss” frames were identical, all participants were more likely to gamble if presented with the loss frame. Those with the “short” gene variant were the most suscetible to the framing effect.

This does not mean that “short” gene participants are more likely to gamble! In a paper published in The Journal of Neuroscience the authors noted “there was no difference in overall risk-seeking behavior” between the two genetic groups. Dr Jonathan Roiser from the UCL Institute of Cognitive Neuroscience, lead author on the paper, explains:

“This doesn’t mean that people with the short variants are risk takers,

“In fact, they were risk averse in the ‘gain frame’ whilst risk seeking in the ‘loss frame’, which implies inconsistency in their decision-making.”

The gene variation isn’t even that important of a factor in making frame effect decisions. Dr Roiser again:

“This one gene cannot tell the whole story, however, as it only explains about ten per cent of the variability in susceptibility to the framing effect. What determines the other ninety per cent of variability is unclear. It is probably a mixture of people’s life experience and other genetic influences.”

Whilst “formula for” stories tend to be what Charlie Brooker called PR-reviewed, with little basis in actual science, “gene for” stories are more normally inaccurately simplified accounts of genuine research. This is the case here, and it’s dangerous. Compulsive gambling can be incredibly destructive, and “it’s not me, it’s my genes” could allow gamblers rationalise their behaviour instead of seeking help.


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