Lost Love Hurts...Literally!

You burn your hand. Ouch! That hurts! So does the breakup of a romantic relationship--but that's a different kind of pain. Right?

Wrong!

Social rejection stimulates increased activity in the same regions of the brain as does physical pain. As far as neurons know, a psychological hurt is no different from a physical one.

So says a new research study published online this week in the Proceedings of the National Academy of Sciences Early Edition. A team of researchers from several US institutions recruited 40 individuals who felt intensely rejected after a recent and unwanted romantic break-up. The volunteers performed two kinds of tasks during functional MRI (fMRI) scanning of their brains. One kind was the Social Rejection task: participants viewed a picture of their former partner and thought about their rejection. The other was the Physical Pain task in which the left forearm was stimulated with an uncomfortable level of heat. For control purposes, these extreme stimuli were compared with alternatives that were more benign: viewing a picture of a friend while recalling a happy time and a merely warm stimulus on the arm. Procedures and statistics controlled for variables including task order and personal traits such as gender, self-esteem, and the length of relationship.

The brain scans revealed that both extreme stimuli (the romantic breakup and the heat) led to overlapping increases in activity in the brain's pain regions, including areas called the dorsal anterior cingulate (dACC) and anterior insula (AI) (see figure). The researchers also found overlapping increases in activity in the thalamus and the right parietal opercular/insular cortex.

Brain scans show significant overlap of the brain regions that process physical and social pain.

"These results give new meaning to the idea that social rejection ‘hurts,'" write the researchers. The investigators offer an evolutionary hypothesis to explain their findings. They suggest that the brain systems that today deal with social rejection co-opted physical pain regions of the brain as human beings evolved as social animals.

They say their findings may lead to new insights into how psychological pain can have physical consequences--as the various somatoform disorders demonstrate. The findings also have implications for basic research on emotion. "Although the experience of social rejection is commonly accompanied by reports of various emotions (e.g., fear, sadness, anger, anxiety, and shame)," the researchers write, "it is generally assumed that these feelings cumulatively give rise to a unique experience of ‘social pain.'" The results of this study are consistent with that view. "The distress elicited in response to intense social rejection may represent a distinct emotional experience that is uniquely associated with physical pain," they conclude.

Sources:

Ethan Kross, Marc G. Berman, Walter Mischel, Edward E. Smith, and Tor D. Wager. Social rejection shares somatosensory representations with physical pain. PNAS (March 22, 2011).

Top graphic from Photobucket.