Older people are less willing to take risks for
potential rewards and this may be due to declining
levels of dopamine in the brain, finds a new UCL
study of over 25,000 people funded by Wellcome.
The study found that older people were less likely
to choose risky gambles to win more points in a
smartphone app called The Great Brain Experiment.
However, they were no different to younger
participants when it came to choosing risky gambles
to avoid losing points. The study shows exactly what
kind of risks older people avoid.
The steady decline in risky choices with age matches
a steady decline in dopamine levels. Throughout
adult life, dopamine levels fall by up to 10% every
decade.
Dopamine is a chemical in the brain involved in
predicting which actions will lead to rewards, and
the researchers previously found that volunteers
chose significantly more risky gambles to win more
money when given a drug that boosted dopamine
levels.
“As we age, our dopamine levels naturally decline
which could explain why we are less likely to seek
rewards,” explains lead author Dr Robb Rutledge (UCL
Institute of Neurology and Max Planck UCL Centre for
Computational Psychiatry and Ageing Research). “The
effects we saw in the experiment may be due to
dopamine decline, since age was associated with only
one type of risk taking and mirrored the known
effects of dopamine drugs on decision making.
Older people were not more risk-averse overall, and
they didn’t make more mistakes than young people
did. Older people were simply less attracted to big
rewards and this made them less willing to take
risks to try to get them.”
The experiment involved 25,189 smartphone users aged
18-69 who played a game in The Great Brain
Experiment smartphone app that involves gambling for
points. In the game, players start with 500 points
and aim to win as many points as possible in thirty
different trials where they must choose between a
safe option and a risky 50/50 gamble.
In the ‘gain’ trials, players can either choose a
guaranteed number of points or a 50/50 chance of
winning more points or gaining nothing. The ‘loss’
trials are the same in reverse, where players can
lose a fixed number of points or gamble with a
chance of losing more points or nothing. In the
‘mixed’ trials, players can choose zero points or to
gamble with a chance of either gaining or losing
points.
On average, all age groups chose to gamble in
approximately 56% of the loss trials and 67% of the
mixed trials. In the gain trials, 18-24 year olds
gambled in 72% of trials and this fell steadily to
64% in the 60-69 age group.
This study also involved mathematical equations
which allowed the authors to make specific
predictions for how loss of dopamine would affect
decision making.
“A loss of dopamine may explain why older people are
less attracted to the promise of potential rewards,”
says Dr Rutledge. “Decisions involving potential
losses were unaffected and this may be because
different processes important for losses are not
affected by ageing.
“Political campaigners often frame voting decisions
negatively, for example saying that UK households
would be £4,300 worse off if the UK decides later
this month to leave the EU rather than £4,300 better
off if the UK decides to remain part of the EU. They
already know that negative messaging helps to
persuade older people, whereas a more optimistic
approach that emphasizes large potential rewards
might appeal more to younger people who are less
likely to vote. Our new findings offer a potential
neuroscientific explanation, suggesting that a
natural decline in dopamine with age might make
people less receptive to the positive approach than
they would have been when they were younger.”
Brexit
EU referendum: UK votes to leave the EU by 52% to
48%.
See also
Brexit (in Italiano)
Link...
For more information
Current biology
Risk Taking for Potential Reward Decreases across
the Lifespan
Robb B. Rutledge, Peter Smittenaar, Peter Zeidman,
Harriet R. Brown, Rick A. Adams, Ulman Lindenberger,
Peter Dayan, Raymond J. Dolan.
Link...
University College London
Link...
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