August 30, 2004
Brain Rewards For Carrying Out Altruistic Punishment

Dominique de Quervain, Urs Fischbacher and Prof Ernst Fehr of the University of Zurich used Positron Emission Tomography (PET) brain scans to watch players carry out altruistic punishment against cheaters.

All 14 players chose revenge whenever the double-cross was deliberate and the retaliation free. Only three retaliated when the double-cross wasn't deliberate. Twelve of 14 players punished a deliberate double-cross even if it cost them more money.

The basic outline of the game which was played repeats the work of one these same researchers, Ernst Fehr, and Simon Gächter of the University of St. Gallen which I reported in my post Altruistic Punishment And Genetic Engineering Of The Mind. My guess is that there is genetic variation in the human population on the extent to which people will feel rewarded for meting out altruistic punishments. That opens up the possibility that once people can control which genetic variations their offspring get they may not opt to pass along all the genetic variations that cause altruistic punishment behavior. This could potentially destabilize society at some time in the future. Also see the related post Emotions Overrule Logic To Cause Us To Punish.

The added twist in the latest work is that the researchers were watching the brains of the players using PET scans while the players inflicted punishments at their own expense.

The researchers determined that deciding to impose this penalty, an altruistic punishment, activated a brain region, the dorsal striatum, involved in experiencing enjoyment or satisfaction.

The dorsal striatum and its most important part, the caudate nucleus, form part of a "reward circuit".

We are wired up to enjoy getting even. The term "sweet revenge" is entirely appropriate. I bet if the brain was scanned while someone ate sweets some of the same circuits would light up.

Altruistic punishment was selected for by evolution. (same article here)

"A lot of theoretical work in evolutionary biology and our previous experimental work suggest that altruistic punishment has been crucial for the evolution of cooperation in human societies," said Ernst Fehr, the senior author of the study who is director of the Institute for Empirical Research in Economics at the University of Zurich. "Our previous experiments show that if altruistic punishment is possible, cooperation flourishes. If we rule out altruistic punishment, cooperation breaks down."

Stanford University psychology professor Brian Knutson wrote an accompanying commentary noting that schadenfreude has now been captured in a brain scan.

The researchers also found that the fantasy of revenge is immensely satisfying: "The activation in the dorsal striatum reflects the anticipated satisfaction from punishing defectors" — or, it appears, from seeing them suffer.

As Knutson notes in his commentary, the Swiss researchers "appear to have captured this complex emotional dynamic of schadenfreude with a PET camera."

There are some interesting aspects of phenomenon. First of all, the brain does reward some types of altruism. But the altruistic act is not experienced subjectivly as a loss because the brain delivers an internal reward that compensates for the loss of resources caused by paying to punish others. Also, the actual act that the brain is rewarded for is essentially painful for the direct target of the act while being beneficial for others since it causes the targets of punishment to be less likely to cheat other people. Altruistic punishment then is quite a complex behavior in terms of its effects.

Share |      Randall Parker, 2004 August 30 03:37 PM  Brain Altruism

Luke Lea said at August 30, 2004 7:56 PM:

An example of group selection, perhaps? Though it also operates within families, as I know from personal experience. So, then, maybe not.

Randall Parker said at August 30, 2004 8:03 PM:

Luke, I think the lack of discernment on whether a punishment is worth delivering is due to the fact that historically humans tended to deal with people they'd deal with again in the future. They didn't have to worry about whether they were punishing someone they'd have future dealings with. So the selection for the punishment urge is really for a behavior that historically more often than not directly benefitted the person meting out the punishment.

Luke Lea said at August 31, 2004 6:36 AM:

Randall, But then it is not really altruistic, is it, but more in the nature of tit-for-tat?

Randall Parker said at August 31, 2004 9:50 AM:


There is motive and there is effect. Under the right conditions the effect is altruistic.

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