The decisions of other people similar to ourselves to take a risk or play it safe influence our own behavior by increasing the subjective value of a particular choice, reports a study published online in Nature Neuroscience. This finding increases our understanding of how social influences affect decision-making and could potentially guide efforts to alter individual decision-making via social factors.
Decisions about risky options are guided by both objective information, such as the likelihood of a particular outcome, and our attitudes towards risk. Other people's decisions are known to influence our own choices of risker or safer options, but it is unknown how we incorporate them with our own preferences to make a decision.
Pearl Chiu and colleagues studied 70 human participants as they made decisions between risky (less probable, but higher payoff) and safe (more probable, but lower payoff) options in a gambling task, either on their own or after observing the choices of others. Participants were more likely to make a choice if they had observed that others had previously made the same choice. This effect was stronger when the choices of others were aligned with a participant's own risk preferences: risk-averse participants were more likely to be influenced by another's choice of a safe option, and vice versa. In a separate experiment, the authors found that risk-taking behavior was not affected when participants were told that a computer had randomly generated the choices they observed.
Using functional magnetic resonance imaging (fMRI), the researchers showed that the increased subjective value of an option due to social influence was reflected in activation of the ventromedial prefrontal cortex, an area known to encode the subjective value of choices.