Until now, researchers could not say whether our
tendency to make fewer risky decisions as we age was due to the wisdom
of growing older, or our brain structures.
The University of Sydney's Dr. Agnieszka Tymula
has for years been studying the factors that influence human
decision-making. The findings suggest that our brain's changing structure, not simply getting older and wiser,
most affects our attitudes to risk.
‘Our attitudes to take risks is better explained by changes in grey matter volume in an area in the brain's right posterior parietal cortex, rather than by age itself.’
Published in Nature Communications
this week, Dr. Tymula and
her co-authors from New York University, Yale University, University
College London and Trinity College show risk aversion is better
explained by changes in grey matter volume in an area in the brain's
right posterior parietal cortex, rather than by age itself.
"We know that as people age, they tend to become more averse to
taking risks," said Dr. Tymula. "Yet, it seems there is something to the
saying that everybody ages at a different pace. Our research suggests
the speed at which our brain's structure changes has a greater impact on
our tolerance of risk than chronological age."
In an experiment, the researchers asked more than 50 adults aged 18
to 88 to make choices between a guaranteed gain of $5 or ambiguous and
risky lotteries with a payout of up to $120. Older participants
preferred the guaranteed option, compared to younger participants.
Surprisingly, when researchers put these data into a model to
determine what best predicted this change in preference, they found it
was primarily driven by the neuronal density - the thickness and
thinness of grey matter - in this brain region, rather than by age.
The results are published in the high-impact journal, Nature Communications
"Globally, we are experiencing an unprecedented demographic shift
with people over 60 expected to outnumber children in only 30 years.
Understanding how such a shift will affect decisions made in our
societies on a political and economic level will be hugely important,"
said Dr. Tymula.
"When we choose our life partners, make a bet with a colleague,
invest in a stock or vote in presidential elections, we cannot predict
with certainty how these decisions will affect us and others.
Understanding the brain's structure can help us predict how our own and
others' decisions will change as our brain ages."