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Physiol Behav. 2014 May 10;130:145-8. doi: 10.1016/j.physbeh.2014.03.032. Epub 2014 Apr 12.

A thermal window for yawning in humans: yawning as a brain cooling mechanism.

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Department of Cognitive Biology, University of Vienna, Vienna, Austria. Electronic address:
Department of Education, University of Vienna, Vienna, Austria.
Farquhar College of Arts and Sciences, Nova Southeastern University, Ft. Lauderdale, USA.
Psychology Department, SUNY College at Oneonta, USA. Electronic address:


The thermoregulatory theory of yawning posits that yawns function to cool the brain in part due to counter-current heat exchange with the deep inhalation of ambient air. Consequently, yawning should be constrained to an optimal thermal zone or range of temperature, i.e., a thermal window, in which we should expect a lower frequency at extreme temperatures. Previous research shows that yawn frequency diminishes as ambient temperatures rise and approach body temperature, but a lower bound to the thermal window has not been demonstrated. To test this, a total of 120 pedestrians were sampled for susceptibly to self-reported yawn contagion during distinct temperature ranges and seasons (winter: 1.4°C, n=60; summer: 19.4°C, n=60). As predicted, the proportion of pedestrians reporting yawning was significantly lower during winter than in summer (18.3% vs. 41.7%), with temperature being the only significant predictor of these differences across seasons. The underlying mechanism for yawning in humans, both spontaneous and contagious, appears to be involved in brain thermoregulation.


Ambient temperature; Contagious yawning; Thermoregulation; Yawning

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