A Calculated Risk


What do you do when you are concentrating really, really hard? You know, when you are drawing something, trying to get the right words of a story down or are doing difficult sums. As kids we would unconsciously stick our tongues out. The more difficult the problem, the farther out our tongues would go. If it was really difficult, we might even screw our faces up.

Clenching our teeth wasn’t something that I remember doing in the face of difficult sums. However, there may well be cultural differences in clenching proclivities in different nationalities. Mizumori at al of U of Osaka have investigated  the effect of clenching on the results in mental arithmetic tests of twenty young adults.

The tests went like this. The participants were given sets of hundred-square calculations to do mentally, four times in all. One of the test series was carried out with the participants clenching and un-clenching their teeth in a rhythmic fashion. The activity of the left jaw muscle (the masseter muscle) was monitored electronically to ensure that clenching activity was absent or rhythmic as appropriate.

The result? Well, clenching doesn’t help with mental arithmetic. Interestingly, the conclusion drawn was that “the results indicate that it may not be harmful for clinicians to encourage their patients to refrain from clenching their teeth.”

It certainly wasn’t harmful to the arithmetic test result and exercise is usually good for the muscles, so maybe it was considered harmful to the teeth. So maybe the best compromise is that if you must clench rhythmically, do it on chewing gum.

  1. doi:10.1016/j.jpor.2010.12.004 

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