The journal Science last week published a study indicating that the reward centres in our brains are highly sensitive to the success of others. In the study, 19 pairs of subjects were presented with a task involving the estimation of the number of dots on a screen, and were then provided with feedback about their perfromance and about a monetary payment that they would receive. They were also provided with the same information about the other member of the pair. Functional magnetic resonance imaging (fMRI) was used to ascertain the effects of this feedback on blood flow in the midbrain-striatal and midbrain-prefrontal dopaminergic projections – parts of the brain implicated in generating subjective rewards, such as positive feelings, in response to achievement. The researchers analysed the cases in which both members of the pair were successful on the task and found that, in such cases, the reward centres activated more strongly in response to a given payment when the other member of the pair received a lower payment than when the other received an identical or higher payment.
The main conclusion that the authors draw from this finding is that it supports the widely held view that subjective rewards are sensitive to the success of others, at least where success is measured in financial terms. Existing studies claiming to support this view have faced difficulties in, among other things, measuring subjective rewards, but the authors of the Science article suggest they they can avoid this difficulty by using activation of the reward centres as an objective proxy for subjective feelings.
Arguably, however, it is hardly surprising that subjective rewards are senstive to the financial benefits enjoyed by others is hardly surprising. Political philosophers have long assumed this to be the case, and though they have perhaps lacked evidence from high quality systematic studies, self-reflection and andecdotal reports from others seem to give ample justification for their assumption.
More interesting, perhaps, it what the study suggests about the possible neural bases of this sensitivity to the success of others. This study may represent a significant step in the attempt to localise and elucidate the neural mechanisms responsible for the sensitivity. And it seems possible that further research of this type may enable the development of, say, pharmacological interventions that could alter the extent to which our subjective rewards track the failure of others.
Would there be any ethical case for altering our tendency to feel good about the failure of others? On the one hand, this tendency is widely regarded is less than virtuous. Other things being equal, most of us respect and admire those who take pleasure in the success of others more than those who are gleeful about their failure. Moreover, it would seem that some of the useful social functions that this tendency serves – for example, motivating achievement in important fields of human endeavour – could be equally if not better achieved by an acute senstivity to our absolute level of achievement rather than our relative financial success. On the other hand, sensitivity to relative financial success may be important in motivating struggles agains the unjust distribution of resources. Perhaps a world of people who were unconcerned about relative success would be one in which unjust social institutions could be introduced with little resistance.
It is important to distinguish here between two different reasons for which we might be sensitive to the financial success of others. One possibility is that our subjective reward is lessened when we perceive that there has been unfairness – such as when another receives more than us for no good reason. The other possibility is that our subjective reward is lessened when others receive more even when this is fair – say, because the other’s greater reward is deserved. It is only the former kind of sensitivity that seems to be important in motivating struggles against injustice.
Interestingly, the study in this week’s issue of Science appears to suggest that both kinds of sensitivity are present. In one brain region studied (the ventral striatum) there was greater activation when the subject received a higher payment than her counterpart than when the payments were the same. Arguably, though, the equal payment was the fairer outcome since performance on the test was similar. It seems then, that we may have some tendency to respond positively to our relative financal success even when that success is unfair or undeserved. However, there were other brain regions (the occipital lobe, angular gyrus, and precuneus/cingulate cortex) where activation was correlated with the other subject receiving a different payment, regardless of whether it was more or less. Perhaps activation in these regions was part of a neural response to perceived unfairness.
References:
K. Fliessbach et al., “Social Comparison Affects Reward-Related Brain Activity in the Human Ventral Striatum,” Science 318, no. 5854 (November 23, 2007), http://www.sciencemag.org/cgi/content/abstract/318/5854/1305
Laura Blue, “Success Depends on Others Failing,” Time Magazine, November 26, 2007, http://www.time.com/time/health/article/0,8599,1687725,00.html