Their conclusion, published in Biology Letters , was that the length of a yawn was a remarkably good predictor of an animal's brain weight, and cortical neuron number--regardless of the size of its skull, or jawbone. Gallup et al. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Full Transcript. Materials provided by University of Vienna. Note: Content may be edited for style and length.
Science News. Story Source: Materials provided by University of Vienna. Journal Reference : Jorg J. A thermal window for yawning in humans: Yawning as a brain cooling mechanism. Yawning frequencies of people vary with temperature of the season.
ScienceDaily, 6 May University of Vienna. Do we yawn to cool the brain? Retrieved November 10, from www. Next, the participants watched a second-long video of nine different people yawning. After watching the clips, they filled out questionnaires answering whether they had the urge to yawn before, during or since. As yawning is contagious, scientists thought this would test whether the temperature of the blood heading to their brain affected this reflex. As expected, the scientists found cooling was linked to fewer yawn urges.
Of the total, 62 participants felt the need to yawn while watching the video. Participants who cooled their brain temperature had less of an urge to yawn than both those in the warm and room temperature groups. A total of
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