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Contagious yawning has been linked to empathy levels in several studies, though not all research supports the association. However, new research in the journal Personality and Individual Differences finds that people with psychopathic traits—especially a lack of empathy—are not as susceptible to catching a case of the yawns ... at least among college students, the only group tested.
Researchers from Baylor University in Texas tried to provoke 135 students to yawn in reaction to someone else's yawn. Each of the participants also completed a questionnaire regarding their personality traits, measuring psychopathic characteristics like selfishness, tendency to be manipulative, impulsivity, and a lack of empathy. Then they sat at a computer and watched 10-second video clips of facial movements, including yawning. Electrodes were attached to their faces just under the lower eyelids, on their foreheads, on the outer corners of their eyes, and on their fingertips to measure their movements in reaction to the videos.
© Wellcome Images via Wikimedia Commons // CC BY 4.0Contagious yawning in a 19th century etching.
"In addition to what he had said about accumulators G. made some very interesting remarks about yawning and about laughter. There are two incomprehensible functions of our organism inexplicable from the scientific point of view,” he said, “although naturally science does not admit them to be inexplicable; these are yawning and laughter. Neither the one nor the other can be rightly understood and explained without knowing about accumulators and their role in the organism. You have noticed that you yawn when you are tired. This is especially noticeable, for instance, in the mountains, when a man who is unaccustomed to them yawns almost continually while he is ascending a mountain. Yawning is the pumping of energy into the small accumulators. When they empty too quickly, that is, when one of them has no time to fill up while the other is being emptied, yawning becomes almost continuous. There are certain diseased conditions which can cause stoppage of the heart when a man wishes but is not able to yawn, and other conditions are known when something goes wrong with the pump, causing it to work without effect, when a man yawns the whole time, but does not pump in any energy.
“The study and the observation of yawning from this point of view may reveal much that is new and interesting.
“Laughter is also directly connected with accumulators. But laughter is the opposite function to yawning. It is not pumping in, but pumping out, that is, the pumping out and the discarding of superfluous energy collected in the accumulators. Laughter does not exist in all centers, but only in centers divided into two halves – positive and negative. If I have not yet spoken of this in detail, I shall do so when we come to a more detailed study of the centers. At present we shall take only the intellectual center. There can be impressions which fall at once on two halves of the center and produce at once a sharp ‘yes’ and ‘no.’ Such a simultaneous ‘yes’ and ‘no’ produces a kind of convulsion in the center and, being unable to harmonize and digest these two opposite impressions of one fact, the center begins to throw out in the form of laughter the energy which flows into it from the accumulator whose turn it is to supply it. In another instance it happens that in the accumulator there has collected too much energy which the center cannot manage to use up. Then eve[n] the most ordinary, impression can be received as double, that is, it may fall at once on the two halves of the center and produce laughter, that is, the discarding of energy. You must understand that I am only giving you an outline. You must remember that both yawning and laughter are very contagious. This shows that they are essentially functions of the instinctive and the moving centers.”