Feeling the Pain of Social Exclusion

In this week's Science there is an interesting report and review article that conclude the emotional pain of rejection is neurologically equivalent to physical pain. This disproves the old maxim, "Sticks and stones may break my bones, but names will never hurt me." Here's part of the review article:

The Greek philosopher Zeno of Citium (356 to 264 B.C.), the founder of Stoicism, considered pain to be one of nine forms of grief. We often speak about the loss of a loved one in terms of painful feelings, but it is still not clear to what extent such metaphors reflect what is actually happening in the human brain? Enter Eisenberger and colleagues (1) on page 290 of this issue with a bold neuroimaging experiment that seeks to discover whether the metaphor for the psychological pain of social loss is reflected in the neural circuitry of the human brain. Using functional magnetic resonance imaging (fMRI), they show that certain human brain areas that "light up" during physical pain are also activated during emotional pain induced by social exclusion.

You might wonder how one measures the feeling of social exclusion while the subject is lying in an MRI machine. Eisenberger et al. circumvented this obvious problem in a clever way. In their study, the 13 participants observed a virtual ball-tossing video game while brain blood flow was monitored by MRI. During a baseline period, subjects were led to believe that they were only observing the game. During the experimental phase, however, they became active participants in the game. Within a few throws of the ball, the two other "players" (actually computerized stooges) stopped throwing the ball to the subjects, leading them to feel excluded (2). The subjects experienced emotional distress as indicated by substantial blood-flow changes in two key brain areas. One of these areas, the anterior cingulate cortex, has been implicated in generating the aversive experience of physical pain. Eisenberger and colleagues demonstrate that the greater the feeling of social distress, the more this brain area becomes activated. The other brain region, in the prefrontal cortex, showed an opposite pattern of activity, becoming more active when the distress was least. In other words, the two brain areas involved in the distressing feelings of social exclusion responded in opposite ways to the degree of social pain experienced. This suggests that the anterior cingulate is more important for elaborating feelings of emotional distress, whereas the prefrontal cortex, already implicated in emotional regulation (3), counteracts the painful feeling of being shunned.

These results are consistent with the idea that aversive feelings of social exclusion and physical pain arise, in part, from the same brain regions. They dovetail nicely with what we know about separation distress in other animals. In our work a quarter of a century ago, we examined the neurochemistry of social attachments in animals (4, 5). We found that the same neurochemicals that regulate physical pain also control the psychological pain of social loss. Indeed, plant opioids (such as morphine) as well as endogenous brain opioids (especially endorphins)--known to alleviate physical pain--also alleviated separation distress (as measured by isolation cries) in dogs, guinea pigs, chicks, rats, and primates (6).

References and Notes

1. N. I. Eisenberger, M. D. Lieberman, K. D. Williams, Science 302, 290 (2003).
2. To visualize the game, see www.psy.mq.ed.au/staff/kip/cyberball.htm.
3. K. L. Phan et al., NeuroImage 16, 331 (2002) [Medline].
4. J. Panksepp et al., Neurosci. Biobehav. Rev. 4, 473 (1980) [Medline].
5. J. Panksepp, in Progress in Theory in Psychopharmacology, S. J. Cooper, Ed. (Academic Press, London, 1981), pp. 149-175.
6. J. Panksepp, Affective Neuroscience (Oxford Univ. Press, New York, 1998) [publisher's information].