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Social and behavioural

Seven ways to be good: 5) Clench your muscles

This post is part of the Research Digest’s Sin Week. Each day for seven days we’ll be posting a confession, a new sin and a way to be good.

11 February 2011

By Christian Jarrett

We tend to associate acts of willpower with people clenching their jaw or fists.

A study published last year showed that this muscular tension isn't merely a side-effect of willpower, it actually helps bolster our self-control [pdf].

Across five studies, Iris Hung at the National University of Singapore and Aparna Labroo at the Booth School of Business showed that various forms of muscle flexion, from fist clenching to calf muscle tightening helped participants to endure pain now for later benefit (e.g. take more time to read a distressing news story about a disaster in Haiti, which in turn led them to give money to a relevant charity in line with how much the story mattered to them); and to resist short- term gain (e.g. snack food) in order to fulfil a long-term gain of better health.

Muscle flexing only worked when participants were already motivated. For example, if long- term health was unimportant to them, muscle flexing made no difference.

So flexing appears to augment willpower rather than changing motivations and attitudes. Muscle clenching was also only effective when performed at the same time as an act of will.