The purpose of yawning might be to cool your brain.

By Seriously Science | April 22, 2014 6:00 am
Photo: flickr/baileysjunk

Photo: flickr/baileysjunk

Wondering what’s been going on lately in the field of chasmology (the scientific study of yawning)? Well, we still don’t really understand why people yawn, but we can add another contender to the list of theories: brain cooling. In this study, the authors showed subjects photos of people yawning to determine their susceptibility to “yawn contagion.” They found that the subjects were more likely to “catch” yawns in the summer compared with the winter. Although there are a number of things that change with the season, the only variable found to correlate with yawning was higher temperature, suggesting that yawns might have a function in cooling the brain (via the release of heat into air in the lungs). So the next time someone gets mad at you for yawning when you should be paying attention, just tell them your brain is hot and you’re cooling it off.

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

“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.”

Related content:
NCBI ROFL: Dogs catch human yawns.
NCBI ROFL: Chasmology: the scientific study of yawning.
NCBI ROFL: An explanation for the shape of the human penis.

CATEGORIZED UNDER: holy correlation batman!, WTF?
  • Keitumetse Mafojane 14003156

    This is pretty interesting as when i think of my own self, I havent been yawning much this autumn/winter. Has there been further research that has been done to prove this? because Ive always been under the impression that yawning is a result of being oxygen deprived.

    KM Mafojane
    14003156

  • http://blogs.discovermagazine.com Michael Keener

    A yawn is a reflex consisting of the simultaneous inhalation of air and the stretching of the eardrums, followed by an exhalation of breath. Pandiculation is the act of yawning and stretching simultaneously.[1]

    Yawning most often occurs in adults immediately before and after sleep, during tedious activities and as a result of its infectious quality. [2] It is commonly associated with tiredness,stress, overwork, lack of stimulation and boredom, though studies show it may be linked to the cooling of the brain.[3] In humans, yawning is often triggered by others yawning (e.g., seeing a person yawning, talking to someone on the phone who is yawning) and is a typical example of positive feedback.[4] This “infectious” yawning has also been observed inchimpanzees, dogs, and can occur across species.[5][6] Approximately 20 physiological reasons for yawning have been proposed by scholars, but there is little agreement about its main functions

  • Keitumetse Mafojane 14003156

    Okay, thank you very much for the feedback, but how do these physiological reasons actually correspond with the actual cooling of the brain?

  • Michael

    I find that I often yawn when I am being engaged in a discussion with co-workers. I’m being serious actually. I don’t know why this happens. But, it always happens if the conversation is not something I want to prolong or engage in and the yawns come on almost annoyingly frequent. Am I changing my breathing patterns, or tensing up in a way that brings about the yawn. It sounds funny I know but it’s true. — (And, yes… they’re usually boring conversations. But, that’s not why I’m yawning. Promise).

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