We yawn when we're tired. We yawn when we're bored. Recent studies also suggest that one purpose of yawning may be to cool our brains. Most people are surprised to find out that yawning can be a signal of anxiety. Anxiety-related yawns tend not to last as long or be as deep as those that have their origins in fatigue.
A similar body language signal is that of false-mastication (false chewing) - that is chewing when there is no food in the mouth. Often the insides of the cheek are "chewed" as well.
See also: Secret # 217: Predicting a Fight Based on Body Language
See also: Secret # 217: Predicting a Fight Based on Body Language
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