Friday, 3 February 2006

Brain scans reveal revenge is sweet for men but not women

How your brain responds to the sight of someone you don’t like having pain inflicted on them could depend on whether you’re a man or woman. Researchers at University College London have observed increased activity in the reward pathways of men’s brains, but not women’s, while they watched someone they didn’t like being hurt.

Tania Singer and colleagues first asked 16 men and 16 women to play a kind of bargaining game in which they were conned by one researcher but aided by another. Later questions confirmed that the participants disliked the person who conned them, but liked the person who helped them.

Next, Singer’s team scanned the participants’ brains, firstly while they had a painful electric shock applied to their hand, secondly while they saw a shock applied to the person who conned them, and finally, while they saw the shock applied to the person who had cooperated with them.

Consistent with past research, the brain scans showed that the same or similar brain areas (the anterior insula, the anterior cingulated cortex) were activated when participants witnessed someone else being hurt, as when they experienced pain themselves. But crucially, for men, this neural simulation of another person’s pain only occurred when they liked the person. If they didn’t like who was being hurt, the male participants instead showed increased activity in the reward pathway of their brain (in the nucleus accumbens). Moreover, this reward-related activity was greater in those male participants who expressed a stronger desire for revenge on the researcher who conned them.

In contrast, the female participants showed an empathic brain response whether they liked the person who was being hurt or not, and their brains did not exhibit reward-related activity when someone they disliked was hurt.

The researchers advised that their findings be treated with caution: “It is possible that our experimental design favoured men because the modality of punishment was related to physical threat, as opposed to psychological or financial threat”. But they added: “Alternatively, these findings could indicate a predominant role for males in the maintenance of justice and punishment of norm violation in human societies”.
Singer, T., Seymour, B., O’Doherty, J.P., Klass, E.S., Dolan, R.J. & Frith, C.D. (2006). Empathic neural responses are modulated by the perceived fairness of others. Nature, 439, 466-469.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Link to previous related Digest item

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