Men Enjoy Physical Revenge, Brain Study Suggests

Researchers have provided the first biologic evidence supporting the idea that people empathize with likeable people in painful situations, and feel satisfaction when someone they dislike suffers.

In particular, men tend to have a taste for physical vengeance, which the researchers suggest could be why men traditionally dominate the world's military and police forces.

Fair play

To get at the issue, scientists set up a game to establish like and dislike between participants and unfamiliar actors. The work is described today in the online version of the journal Nature.

Each participant was given a certain amount of points and could decide whether to keep them or give them to the other player. The other player, the actor in this case, could then decide to return some or all of the points to the participant. Each transaction would result in the tripling of points. The fair way to play is for both players to send all or most points back and forth, and keeping all the points for yourself is considered unfair.

The researchers set up the game so participants would play one game against an actor instructed to play fairly, and another against an actor playing unfairly.

In a post-game survey, both male and female participants rated the fair actor as being significantly more fair, more agreeable, more likeable, and even more attractive than the unfair player.

Shocking method

The next step involved scanning the participant's brain activity as electric shocks were doled out to themselves, a likeable "fair" actor, and a disliked "unfair" actor.

"When you see someone receiving a shock, you have activations in the pain-related area of your brain," study co-author Klaas Stephan of University College London told LiveScience. "We established that it makes a difference if you like the person receiving the shock. Empathy active regions are affected by your connection to people."

When the likeable actor received a painful shock, researchers registered a spike in activity in pain-related areas of the participants' brains, indicating they empathized with the actor's pain.

When the disliked actor received a shock, however, the scans showed a slightly smaller activity spike in women and none at all in men, indicating that participants felt less compassion—and perhaps satisfaction—for the disliked actor.

"Females still have an empathetic, although reduced, response to unfair players, but in males the response more or less disappears," Stephan said. "We found in the post-scan questionnaire that male subjects expressed higher levels of desire for revenge than females. This was mirrored in the brain, as activity showed a tight correlation with desire for revenge."

Suitable punishment?

The strong gender difference could have been driven by the type of punishment, however.

"If we had chosen a different type of punishment, say social punishment, then women might have shown a different reaction," Stephan said.  

Regardless, it does suggest that men are more responsive to the idea of physically punishing evil-doers. The authors suggest that this preference, based on this new evidence, could have played a role in shaping justice systems throughout history.

"When you look across societies in the world, then traditionally both police and armed forces have consisted of men, although that is changing in the western world," Stephan said. "That could be a culturally determined thing, or it could be that there are biological variables that favor men taking on these roles. We cannot say on the basis of this study, but it's an interesting speculation. Males seem to have a stronger tendency to favor physical punishment for people who have behaved in an uncooperative or unfair manner."

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