How scientists can tell when your motives are truly altruistic

There are plenty of generous people in the world who choose to donate huge sums of money and expect nothing in return aside from, say, their name engraved in 3-foot high letters on a major landmark. Of course, you might suspect them of having some ulterior motive, but it’s very hard to prove that they aren’t simply the giving type.

But researchers have made a significant step in uncovering altruistic frauds. A paper published in Science earlier this month showed that certain brain regions interact differently depending on whether an altruistic deed is motivated by empathy or reciprocity (doing a good deed only to get something in return). And so it’s possible to predict the motivations of a particular action by looking at brain activity under functional magnetic resonance imaging (fMRI) scans.

Yosuke Morishima, researcher in the psychiatric neurophysiology department at the University Hospital of Psychiatry in Switzerland who worked on the study, tells Quartz that people may behave the same way whether motivated by altruism or more selfish reasons.

“Our study shows we do need brain imaging to understand our behavior. We can’t know the underlying motive based on behavior alone,” he says.

Researchers, led by behavioral economist Ernst Fehr from the University of Zurich, divided subjects into two groups. The first group was tested on empathy-induced altruism by watching a partner receive pain shocks. The second group was tested on reciprocal altruism by receiving painful shocks dependent on their partner’s behavior–if the partner gave up money, they would receive less shocks. Both groups had a control partner who was not involved in such empathy or reciprocity-inducing behavior. The subjects then had to decide how to share money between themselves and their partners.

The fMRI scans of brain activity while subjects were making these decisions showed similar activity within the anterior insula, anterior cingulate cortex, and ventral striatum regions of the brain.

However, the interactions between these three brain regions were considerably different depending on whether the subject was in an empathetic or altruistic situation. Based on these differences, the researchers were able to predict, with 80% accuracy, whether actions were motivated by empathy or reciprocity.

The researchers then sorted subjects into two groups—pro-social and selfish—depending on the frequency with which they gave away money. They once again tested the effects of inducing empathy and reciprocity, and found that for selfish people, it was possible to enhance altruistic behavior using empathy—but not reciprocity. For pro-social people, the opposite was true. They became even more altruistic in a reciprocal setting, but not in the empathy context.

In the long term, Morishima says the understanding of how brain activity connects to motives could be used for lie detection tests. However, he notes that the prediction rate was only 80%, and “the technology is still too primitive” for such practical uses.

Axel Cleeremans from the Université Libre de Bruxelles, who was not involved in the study, tells Quartz that such work is “the future.”

The connection between motives and brain states raises “interesting questions” and “complicated answers,” he says.

“There’s no question mental states can be analyzed in terms of brain states,” adds Cleeremans. “The researchers show it is the functional activity between these brain regions that play the explanatory role in terms of accounting for the different motives of the different participants.”

It will be several years, if not decades, before such work is applicable outside the lab. But at least it offers some hope for uncovering the true motives of those suspiciously generous philanthropists.