Guest blog – Dr Robb Rutledge, Senior Research Associate, Wellcome Trust Centre for Neuroimaging, UCL – Declining dopamine may explain why older people take fewer risks

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In our daily life, we frequently make decisions where the outcome is uncertain. Where should I go for lunch? Which way should I go to get home from work? Should I vote for Britain to leave or to remain in the European Union?

How do we decide when the risk is worth it? Older people are often said to be more risk-averse than younger people. In a recent study published in the scientific journal Current Biology, we reported that getting older affects risk taking in one specific way and natural decline in the brain chemical dopamine may be responsible.

We used a smartphone app called The Great Brain Experiment to study how getting older affects the choices made by 25,189 people around the world. In one game, players started with 500 points and tried to win as many points as they could. In some trials, they couldn’t lose. They chose between a safe option like gaining 50 points for sure and a risky option like spinning a spinner with equal chances of winning 120 points or nothing. In other trials, they couldn’t win. They chose between a safe option like losing 50 points for sure and a risky option with equal chances of losing 120 points or nothing.

We found that older people were less likely to take risks to try to win bigger prizes. However, they were no different to younger participants when it came to taking risks to avoid losing points, when there were only potential losses. It is widely believed that older people don’t take risks, but our study shows exactly what kind of risks older people avoid. Older people were not more risk-averse overall. They were simply less attracted to big rewards and this made them less willing to take risks to try to get them.

The brain chemical dopamine gradually declines as we age, with dopamine levels falling up to 10% every decade. Dopamine is a chemical involved in predicting which actions will lead to rewards. In a study published last year in the Journal of Neuroscience, we reported that volunteers chose significantly more risky gambles to win more money after being given a drug that boosted dopamine levels. We found that getting older had exactly the opposite effect on risk taking, reducing risk taking specifically in situations with potential rewards but not potential losses. Natural decline in dopamine could explain why we are less likely to seek rewards as we age.

Fortunately, financial decisions generally involve both potential gains and losses, suggesting that age-related changes in dopamine may not affect the important financial decisions we make. We also found that, for the simple decisions we studied, older people didn’t make more mistakes than young people did and were just as consistent in their economic preferences. This is good news, because it means that the gradual loss of dopamine that occurs with aging doesn’t affect most of the simple economic decisions that we make.

Voting decisions are often framed negatively, saying for example that UK households would be £4,300 worse off if the UK decides 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 can be effective in persuading people. A more optimistic message about the potential rewards of remaining part of the EU might appeal more to a younger audience. Our results suggest a possible neuroscientific explanation. Gradual decline in dopamine makes the potential reward of a risky decision less attractive, and makes us less likely to take the risky choice than we would have when we were younger.

The Great Brain Experiment smartphone app is available for free for iPhone and Android systems. All are invited to play the eight different games and to contribute to scientific research on ageing.

ILC-UK has a Memorandum of Understanding with University College London led by the UCL Grand Challenge of Human Wellbeing.

Rutledge RB, Smittenaar P, Zeidman P, Brown HR, Adams RA, Lindenberger U, Dayan P, Dolan RJ (2016) Risk taking for potential rewards decreases across the lifespan. Current Biology 26, 1-6.

Rutledge RB, Skandali N, Dayan P, Dolan RJ (2015) Dopaminergic modulation of decision making and subjective well-being. Journal of Neuroscience 35, 9811-9822.

Dr Robb Rutledge
Senior Research Associate
Wellcome Trust Centre for Neuroimaging, UCL

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