Perceived intentions influence brain response

When people judge another's actions, they often consider both the other person's outcome and their intentions. For example, in deciding whether a car salesperson's price is fair, people take into account both the price itself and their judgment of how honest the salesperson seems. To investigate how the brain combines these two kinds of information, researchers at the Trinity College Institute of Neuroscience in Dublin, Ireland, used functional magnetic resonance imaging to examine volunteers while they made judgments about others.

Participants observed players in a group economic game in which contributing benefitted the group and not contributing benefitted the individual players. Importantly, some participants had a "Donation" game with instructions about charity for the group, while the other participants had the same game described as a "Savings" game with instructions referring to risky investing and the stock market.

"We designed the framing conditions to engage or disengage participants' emotional response to the game, which meant that we could change how participants judged others without changing what they actually did," explains lead study author Dr. Jeffrey C. Cooper.

The researchers found that participants in the "Donation" game liked the generous players and disliked selfish ones, but for participants in the "Savings" game, generosity did not affect liking. The ventromedial prefrontal cortex (VMPFC), which has been associated with responding to personal rewards, showed a similar pattern. In the "Donation" game, it activated when observing generous play and deactivated when observing selfish play, but in the "Savings" game, it did not respond.

"Generous and selfish players made the same contributions in both conditions, but people only liked them differently when we described their actions in terms of consequences for the group, and only then did the VMPFC respond to those actions," says Dr. Cooper.

The findings suggest that how the brain represents others' actions depends crucially on whether we perceive their intentions as helpful or harmful and that those intentions can be changed by a brief description. "These findings show for the first time that just seeing someone's action described as kind or foolish can change an important neural representation of how rewarding that action is to us," concludes Dr. Cooper.

The researchers include Jeffrey C. Cooper, Tamar A. Kreps, Taylor Wiebe, Tristana Pirkl, and Brian Knutson, Stanford University, Stanford, CA.