Genetic link to 'failing to learn from mistakes'

Our ability to learn from making mistakes may be linked to whether or not we carry a particular gene variant which affects our brain's reward system, according to research published last week in the journal Science. The discovery may help to explain why the variant has previously been linked to addiction, say the team.

When we carry out an action with positive consequences, it triggers our brain to reward us by increasing levels of a pleasure chemical called dopamine, thus helping us to learn to repeat that action in the future. In the absence of such triggers, dopamine levels drop removing the incentive to carry out that action again.

Individuals carrying the gene variant - called A1 - have less dopamine docking stations; reducing any reward that they may experience in response to a beneficial action and, in theory, making it harder for them to 'learn from their mistakes'.

The researchers, based at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, looked at 26 men - twelve of which had the A1 gene variant. The ability of each volunteer to learn to repeat a beneficial action was tested by asking them to choose between pairs of random symbols on a computer screen and asking them to work out which had positive consequences. After each selection, either a smiling or frowning face would appear to signify whether their choice was positive or not.

The researchers found that those with the A1 variant found it harder to work out which symbols triggered positive consequences, suggesting that they were less successful at learning to avoid mistakes. Brain scans indicating that areas of the brain thought to be linked to learning were more active in those lacking the A1 gene variant supported these findings.

Although the research suggests that 30 per cent of people carry one copy of the gene variant and three per cent may carry two, it is important not to jump to any conclusions says study co-author Tilman Klein. 'One has to be cautious be saying that 30 per cent are affected - we just found that they have problems in learning to avoid negative action outcomes. But the situation we tested them was an artificial laboratory setting. Therefore more research is needed to show how our findings apply to real world situations', he told The Daily Telegraph.

The discovery may help to explain why the variant has previously been linked to addictive and compulsive behaviours, but it is by no means the full picture said Klein. 'It's our strong belief, that the variant we investigated here is not the only cause for example of an addiction - but maybe it contributes to a predisposition for developing an addiction'. he explained to The Daily Telegraph.