Friday, July 15, 2011

Take two Tylenol for heartache too

Last summer, I was playing badminton with my kids, and I tore a calf muscle.  It hurt.  A lot.  Language has lots of ways to express pain.  In the case of my calf, the pain was intense.  The pain shot through my entire leg.  And when the muscle would spasm, I would feel a burning pain.

It is interesting that people also use the language of pain to talk about social pain.  We talk about the pain of a breakup.  Musicians sing about their heart aching for someone they miss.  When people recall being teased as a child, they invariably talk about how much it hurt. 

Is this just a metaphor?

This question was examined in a clever paper by Nathan Dewall, Dianne Tice, Roy Baumeister, and their colleagues in a paper in the July, 2010 issue of Psychological Science.

They reasoned that if we really feel pain from social difficulties, then the strength of that pain might be relieved by taking a pain relieving drug that works on the way the brain processes pain.  One such drug is acetaminophen (the active ingredient in Tylenol). 

In one study, participants in an experimental group took two acetaminophen pills each day, while the control group took a placebo.  Each day, people rated themselves on a scale designed to measure hurt feelings.  At the start of the study, the two groups had similar levels of hurt feelings.  By the end of the study 3 weeks later, people rated themselves as having a lower level of social pain than people who took the placebo.  There was no placebo effect in this study at all, in fact.  People taking a placebo experienced about the same level of hurt feelings throughout the study.

A second study used functional Magnetic Resonance Imaging (fMRI) to look at the brain’s response to pain.  Participants either took acetaminophen or a placebo for 3 weeks before the imaging study.  Then, while in the MRI scanner, people played a game in which they thought they were passing a virtual ball with a group of two other participants.  In one round of the game, the participant had the ball thrown to them frequently.  In another round, the participant was excluded, and the other two players (who were actually computer opponents) threw the ball only to each other. 

Functional Magnetic Resonanace Imaging gives a measure of the amount of blood flowing to different areas of the brain.  Because the brain needs a lot of glucose to act, regions of the brain that are very active when people do some task experience an increase in blood flow.  So, blood flow is a rough marker of the activity of the brain.

In this study, the authors looked at two regions of the brain that are involved in the perception of pain (the dorsal Anterior Cingulate Cortex and the Anterior Insula for those of you who like your brain areas…).  People who took a placebo showed higher levels of activity in these brain regions when being excluded from the game than when being included.  In contrast, the people who took acetaminophen actually showed about the same level of activity in the brain regions associated with pain in both when being excluded and included in the game, suggesting that they did not experience an increase in physical pain when being socially excluded.

These findings suggest that the words to the old song, “Sticks and stones may break my bones, but words will never hurt me” are not quite right.  We really do experience social pain as physical pain.

It is not surprising that the brain would use the mechanisms of pain for social exclusion and other social difficulties.  As humans, we are social creatures.  We rely on our social relationships to survive.  Pain is used as a signal of damage to our bodies, because that helps us to protect ourselves.  It should be no surprise that potential damage to our social relationships is also marked by pain.