Yina Ma and her team at Peking University scanned the brains of 33 student participants while they watched numerous video clips of people being pricked painfully in the face or hand by a needle, or touched on those same parts by a cotton bud (referred to as a Q-tip in the US). Extra activity in the brain, in response to the needle clips versus cotton bud clips, was taken to be a neural marker for empathy (seeing someone else in pain is known to trigger activity in the pain matrix of one's own brain).

The participants also rated their own empathy levels and their subjective sense of their socio-economic status. They were shown a ladder with ten rungs, with the top rung representing people with the best jobs and education and most money; participants then indicated which rung they saw themselves as occupying. Although the participants were students at the same university they varied in their subjective sense of status. Finally, the participants were left alone in a room with an anonymous donation box, labelled as raising money to help impoverished patients with cataracts.

Among patients who considered themselves privileged in terms of socio-economic status, there was a positive relationship between empathy and altruism. The more neural signs of empathy they displayed in the scanner (based on extra activity in the left somatosensory cortex when viewing needle clips), the more empathy they said they had, and the more money they chose to donate to charity. By contrast, among participants who considered themselves lower in socio-economic status, the opposite pattern was observed. The greater their empathy-related brain activity in the scanner (based on extra right somatosensory cortex and inferior frontal cortex activity in response to needle clips), the less empathy they said they had, and the less money they chose to donate to charity. The researchers said the empathy-related inferior frontal cortex activity observed in these participants could be a sign of inhibitory processes quashing the emotional impact of seeing another person in pain.

Note, there was no absolute difference in the amount of money donated by participants who self-identified as low or high socio-economic status. The finding is more subtle and suggests empathy has a differential effect on our altruistic behaviour depending on how we see our standing in the world.

"Our findings have significant implications to the social domain," the researchers said, "in that, besides improving objective socio-economic status, raising subjective socio-economic status via education may possibly manifold altruistic behaviours in human society."

The findings add to a complex literature that suggests lower socio-economic status is sometimes associated with more empathy and altruism (http://psycnet.apa.org/journals/psp/99/5/771/), but sometimes associated with reduced empathy (http://www.sciencedirect.com/science/article/pii/S0140197105001090).

Ma, Y., Wang, C., and Han, S. (2011). Neural responses to perceived pain in others predict real-life monetary donations in different socioeconomic contexts NeuroImage, 57 (3), 1273-1280 DOI: http://dx.doi.org/10.1016/j.neuroimage.2011.05.003

From BPS Research Digest