Ageing may cloud your financial judgement, thanks to 鈥渘oise鈥� in an area of the brain critical for predicting pay-offs, suggests a study of people who played an investment game in a brain scanner.
and of Stanford University in California, scanned the brains of 110 men and women aged 19 to 85 with functional MRI as they played 100 rounds of a game in which they had to choose one of three possible investments.
One was in a safe bond that always delivers $1, another was a stock twice as likely to pay off $10 than to lose $10. The third was a highly risky stock with those odds flipped. 鈥淲hat we鈥檙e doing is trying to get closer and closer to real investing,鈥� Samanez-Larkin says.
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Shrewd investors will keep picking bonds until they figure out which is the profitable stock. The researchers found that volunteers between 67 and 85 took longer to figure this out than their younger counterparts. 鈥淲hen older adults are choosing risky assets they make more errors,鈥� says Samanez-Larkin.
Reward sensor
What鈥檚 more activity in the striatum, a region critical to sensing reward, was more sporadic in these older volunteers 鈥� this area only lit up strongly in some rounds, whereas in younger volunteers activation was consistent.
Samanez-Larkin suggests the fluctuating activity could act like noise, clouding someone鈥檚 ability to work out the best investment.
鈥淭his part of the brain seem to be very important for learning from past history about whether something that happens is good or bad,鈥� says a neuroscientist at Duke University in Durham, North Carolina.
When Samanez-Larkin repeated the game but this time told elderly volunteers what the stakes were, this prompted them to invest just like younger players.
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