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Smiling & Pain

Smiling & Pain Photo Credit: Clipart.com

Smiling, even with no emotion behind it, may help people tolerate pain. 


Transcript

Smiling versus pain. I'm Bob Hirshon and this is Science Update.

If you’re getting a shot at the doctor’s office, you may not feel like smiling. But psychologist Sarah Pressman of the University of California at Irvine and her colleagues may have found a reason to try it anyway. Her team found that people who smiled while getting a needle reported up to 40 percent less pain than people who didn’t. That’s despite the fact that they were essentially tricked into smiling by positioning chopsticks in their mouths.

Pressman:
And they don’t know that they’re smiling, they just think they’re doing these different weird positions for a multitasking study, while getting a needle.

The smilers also showed less physiological stress as measured by heart rate and skin conductance. Next, Pressman plans to try a similar experiment with kids, and to look more closely at how the muscular action of smiling can produce results like these. I’m Bob Hirshon for AAAS, the Science Society.


Making Sense of the Research

Have you ever heard the advice “fake it til you make it,” meaning act like you've achieved something until you really do achieve it? Research indicates that this may be true of smiling. 

Scientists and anthropologists have long known that smiling is a universal human trait—across cultures and languages, in all parts of the world, a smile indicates happiness or pleasure. Then some scientists started wondering if it works the other way around: whether smiling can actually create good emotions, or moderate bad ones.

One of the first major studies that looked into this was published in 1983 in the journal Science. University of Washington psychologist Marsha Linehan and her colleagues found that when people altered their facial expressions on a purely muscular level, their emotions were affected, and so was activity in the nervous system associated with positive or negative emotions. 

Since then, many studies have shown that facial expressions really can influence how we feel, and not just show it. In one particularly memorable experiment, psychologists at the University of Cardiff in Wales found that people who had received Botox treatments, which stiffens the face and makes frowning more difficult, reported being more happy than comparable non-Botoxed people. 

In this study, Pressman's team looked at the effects of smiling on pain tolerance. Past work had already indicated that smiling could have this benefit. Their study focused on a very specific experience—an injection—and also took care to remove the volunteers' existing knowledge of what smiling means out of the picture.

How did they do that? They didn't tell the subjects that the study had anything to do with smiling. Instead, they said it was about “multi-tasking.” They said that they wanted to keep the subjects occupied with a muscular task by holding chopsticks in their mouth in different positions. What the volunteers didn't know was that these chopsticks were being carefully arranged to produce very specific types of smiles.  

After doing some tasks that were basically designed to mislead the subjects about the study's true intention, they were told they would be getting an injection. Volunteers not only reported less pain when their facial muscles had been manipulated into a smile, but their bodies also showed signs of reduced stress (changes in heart rate and electrical conductance across the skin).

Pressman says her team isn't sure if telling someone to smile would have the same effect, since people might resist the idea of smiling when they don't want to. However, if they can get people to do it consistently, especially children, it could be a safe, effective, and cost-free form of pain management.

Now try and answer these questions:

  1. What was known before this study about the effects of smiling?
  2. What did the researchers find out about smiling in this study?
  3. How did the researchers make sure the subjects didn't know they were being made to smile? Why was this important?
You may want to check out these related Science Updates:
 

In Depression Prevention Training, learn how scientists are trying to prevent depression by training kids to gravitate toward positive faces.

REM sleep, in which dreams occur, may help take the edge off emotional pain. To learn more, see the Science Update Dreams and Emotions.

For a fun tangent on smiling, learn about the science behind the Mona Lisa's Smile.


Going Further


For Educators

In Depression Prevention Training, learn how scientists are trying to prevent depression by training kids to gravitate toward positive faces.

REM sleep, in which dreams occur, may help take the edge off emotional pain. To learn more, see the Science Update lesson Dreams and Emotions.

For a fun tangent on smiling, learn about the science behind the Mona Lisa's Smile.


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