Science has a paper by de Quervain et al. on “altruistic punishment”, the irrational behavior of seeking to punish those who transgress societal “rules” where there is no benefit for the punisher.
The researchers found that when a subject both felt an urge to “punish” and could do so effectively, both the caudate nucleus and the thalamus had higher levels of activation. They also found that the degree of activation of the caudate nucleus was directly related to the “cost” that the punisher was willing to bear in order to punish. The caudate nucleus is already known as a key component in “reward processing” in humans. In other words, punishing the guilty is self-rewarding for humans. The authors come to this conclusion:
Our study is part of recent attempts in “neuroeconomics” and the “cognitive neuroscience of social behavior” to understand the social brain and the associated moral emotions (37–44). However, this study sought to identify the neural basis of the altruistic punishment of defectors. The ability to develop social norms that apply to large groups of genetically unrelated individuals and to enforce these norms through altruistic sanctions is one of the distinguishing characteristics of the human species. Altruistic punishment is probably a key element in explaining the unprecedented level of cooperation in human societies (1–3). We hypothesize that altruistic punishment provides relief or satisfaction to the punisher and activates, therefore, reward-related brain regions.
This brings up another possible avenue of research: does vicarious experience of “altruistic punishment” also light up the caudate nucleus? I’m going to speculate wildly here and give my opinion that if this line of research is carried out, it will find that experiences like watching a film based upon the portrayal of “altruistic punishment” results in activation of the caudate nucleus. This would, of course, provide a biological basis for why our popular media is awash in violence, and a reason for the otherwise unreasonable success of movies such as “Death Wish”. If the graded response of the caudate nucleus in the present study indicates something in this regard, perhaps it is that in order to increase the activation of the caudate nucleus (or induce it at all) through vicarious experience, one has to present more intense “punishments” for ever-plainer violations of social rules. This also would explain a lot if true. Now, we just need to convince people to put up with PET scans and the like while watching the latest revenge flick from Hollywood…
de Quervain, D.J.-F., Fischbacher, U., Treyer, V., Schellhammer, M., Schnyder, U, Buck, A., and Fehr, E. 2004. “The Neural Basis of Altruistic
Punishment.” Science 305:1254-1258.
(Trackback added for Carl Zimmer’s post on ‘spite’ in bacteria. I don’t think that the bacteria will be into vicarious experience…)