The following is from the magazine The Annals of Improbable Research.
Compiled by R.G. Briskett, AIR staff
Yawning has induced tremendous enthusiasm among scientists. These particular scientists are small in number, partly because funding for yawn experiments is rather limited. Despite the dearth of laboratories, equipment, professorships, or prize money dedicated to the subject, yawning can be of great appeal to an experimentalist. A yawn is rather mysterious-- a gaping, black hole that invites anyone -- anyone of a certain sensibility, that is -- to come, take a look, and take a poke at teasing out some of its secrets.
Here are a few of the many experiments that have been documented.
Yawning in Church and in School
Joseph E. Moore of the Jesup Psychological Laboratory at George Peabody College in Nashville, Tennessee conducted several key experiments more than a half-century ago:
“Some Psychological Aspects of Yawning,” J.E. Moore, Journal of General Psychology, vol. 27, 1942, pp. 289-94. Moore’s key findings are revelatory:
In this investigation trained yawners apparently stimulated college students in assemblies and libraries to yawn as well as church goers in both the morning and evening services.
The phonograph record stimulated some of the blind subjects but few of the graduate nurses to yawn.
Motion pictures of a girl yawning seemed to initiate the yawning reflex in several students taking general psychology.
Yawning at Temple
Ronald Baenninger is a professor of psychology at Temple University in Philadelphia. He is a former engineer, and is now editor-in-chief of the research journal Aggressive Behavior. Professor Baenninger has conducted a number of yawning experiments. Much of this yawning occurred in Temple students. One of Baenninger’s most basic experiments reflects an engineer’s appreciation of proper measurement. Because later experiments would depend on having students observe,
record, and report their own yawns, he performed a calibration. This gave him a gauge that was useful in later experiments. Details can be found in:
“Self-Report as a Valid Measure of Yawning in the Laboratory,” Monica Greco and Ronald Baenninger, Bulletin of the Psychonomic Society, vol. 27, no. 1, January 1989, pp. 75-6. The basic assessment technique was simple:
30 undergraduate students were assigned to 1 of 2 groups that recorded their own yawns either in complete privacy or videotaped through a 2-way mirror.
Having ascertained how much he could trust what his students would report about their own experiences, ProfessornBaenninger, together with his colleagues, threw himself into a full-bore examination of when, where, and why students yawn. The trio of Greco, Baenninger and Govern published its results in 1993:
“On the Context of Yawning: When, Where, and Why?” Monica Greco, Ronald Baenninger and John Govern, Psychological Record, vol. 43, no. 2, Spring 1993, pp. 175-83.
From personal logs kept by 28 subjects of their yawning during 1 week we found that yawns occurred during the hours of transitions between sleeping and waking. During the day yawns were associated with attending class, driving, studying or reading, and watching television. A survey of a much larger sample of subjects disclosed some agreement, but several discrepancies between what respondents believed about their yawning and the actual behavior of those subjects who kept logs.
Professor Baenninger later drew on these, and other, findings to publish a wonderful bedtime read:
“On Yawning and Its Functions,” Ronald Baenninger, Psychonomic Bulletin and Review, vol. 4, 1997, pp. 198-207.
One of the studies, especially, set the tone that research need not be conducted only in a laboratory:
“Field Observations of Yawning and Activity in Humans,” Ronald Baenninger, Sue Binkley and Maryann Baenninger, Physiology and Behavior, vol. 59, no. 3, March 1996, pp. 421-5. The three authors report a memorable discovery that might have eluded scientists who study only lab animals:
More yawning occurred during the week than during weekends.
The Binkley who teamed up with Baenninger for that 1996 experiment is the same Binkley who produced two of the best-loved (if not always-best-appreciated) studies on the subject of human physiological rhythms:
“Weekly Phase Shifts of Rhythms Self-Reported by Almost Feral Human Students in the U.S.A. and Spain,” Sue Binkley, Maria Begona Tome and Karen Mosher, Physiology and Behavior, vol. 46, 1989, pp. 423-27.
and
“Wrist Activity in a Woman: Daily, Weekly, Menstrual, Lunar, Annual Cycles?” Sue Binkley, Physiology and Behavior, vol. 52, 1992, pp. 411-21
Do Men Yawn More Than Women?
Men are not women, and women are not men. Two researchers in Rome, Italy -- Gabriele Schino of Istituto di Psicologia del CNR, and Filippo Aureli at Università di Roma “La Sapienza” -- noticed this key difference. They formulated a hypothesis, and then set out to test it:
“Do Men Yawn More Than Women?” Gabriele Schino and Filippo Aureli, Ethology and Sociobiology, vol. 10, no. 5, July 1989, pp. 375-8.
Tested the hypothesis that the sex differences in the frequency of yawning are related to sexual dimorphism in canine size, using human passengers on the Rome underground in Italy. The relative percentages of males and females present during data collection were 59.3% and 40.7%, respectively. A total of 267 yawns by 221 different persons (57.9% males, 42.1% females) were recorded. Males and females, unlike several nonhuman primate species, did not differ in the frequency of yawning, although uncovered yawns were more frequent in men than in women. It is suggested that sex differences in frequency of yawning by primates may be related to the sex dimorphism in canine size.
Probing the Yawns of Boredom
Robert R. Provine of the University of Maryland (an institution that in fact has two Robert Provines) is known for his many studies of laughter. Perhaps of greater import, Provine has also delved deep into yawning, producing several publications.
“Yawning: Effects of Stimulus Interest,” Robert R. Provine and Heidi B. Hamernik,
Bulletin of the Psychonomic Society, vol. 24, no. 6, November 1986, pp. 437-8.
The hypothesis that subjects yawn more while observing uninteresting than while observing interesting stimuli was tested by comparing the yawns produced by 32 male and female college freshmen while they observed a 30-minute rock video -- a complex and interesting audiovisual stimulus -- and a 30 min color-bar test pattern without an audio track, an unchanging and very uninteresting stimulus. Significantly more and longer yawns were produced during the uninteresting stimulus than during the interesting stimulus, and males had longer yawns than females. The folk belief that people yawn more during boring than interesting events was confirmed.
Provine also squarely faced up to an ancient question, one that’s been much debated on all levels of society:
“Faces as Releasers of Contagious Yawning: An Approach to Face Detection Using Normal Human Subjects,” Robert R. Provine, Bulletin of the Psychonomic Society, vol. 27, no. 3, 1989, pp. 211-4.
360 psychology students were divided into 12 experimental groups and participated in a single experimental session. The yawn-evoking potency of variations in a 5-min series of 30 videotaped repetitions of a yawning face were compared with each other and with a series of 30 videotaped smiles to determine the ethological releasing stimulus for the fixed-action pattern of yawning and to understand the more general process of face detection. Animate video images of yawning faces in several axial orientations evoked yawns in more Subjects than did featureless or smiling faces, and no single feature, such as a gaping mouth, was necessary to evoke yawns. The yawn recognition mechanism is neither axially specific nor triggered by an isolated facial feature.
The Stimulation of Reading
Mary Carskadon of Brown University in Providence, Rhode Island read about Robert Provine’s
experiments. Thus stimulated, Carskadon set herself a goal: “to examine whether reading about yawning is a specific releaser of yawning or reading about opening the mouth for another purpose might effective as well.” And she met that goal:
“Yawning Elicited by Reading: Is an Open Mouth Sufficient Stimulus?” Mary A. Carskadon, Sleep Research, vol. 20, 1991, pp. 1-16.
While seated in a large auditorium, students ... were given one of two brief passages to read, with instructions to “remain absolutely quiet and do not look around the room” while reading. ... One passage (“Yawn”) described yawning... The second (“Open Wide”) ... described tonsils and tonsillitis in the context of explaining why a doctor says “open wide and say ah”. ... Subjects were then requested to answer questions about whether they yawned, were tempted to yawn, did not yawn, or could not remember having yawned while reading the text. ... Reading about yawning was significantly more likely to elicit yawning behavior than reading about opening the mouth per se.
Chimpanzee See, Chimpanzee Do
Other scientists, too, were stimulated by Robert Provine’s research. A team of British and Japanese researchers showed that some of Provine’s findings apply to more than just human beings. This was something mildly unusual in modern science -- scientists trying to replicate in experiments with chimpanzees something that they had first seen in experiments with humans:
“Contagious Yawning in Chimpanzees,” James R. Anderson, Masako Myowa-Yamakoshi and Tetsuro Matsuzawa, Proceedings of the Royal Society B, vol. 271, no. 1, supplement 6, December 7, 2004, pp. S468-S470.
Six adult female chimpanzees were shown video scenes of chimpanzees repeatedly yawning or of chimpanzees showing open-mouth facial expressions that were not yawns. Two out of the six females showed significantly higher frequencies of yawning in response to yawn videos; no chimpanzees showed the inverse. Three infant chimpanzees that accompanied their mothers did not yawn at all. These data are highly reminiscent of the contagious yawning effects reported for humans. Contagious yawning is thought to be based on the capacity for empathy. Contagious yawning in chimpanzees provides further evidence that these apes may possess advanced self-awareness and empathic abilities.
(Image credit: Flickr user Sean Malone)
Yawning on, and in, the Brain
The neurobiology of yawning has its own varied and tantalizing literature. Wave upon wave of new biomedical technology has promised, and does promise, to yield up great, deep insights. A soon-to-be published article is outstandingly typical:
“Yearning to Yawn: The Neural Basis of Contagious Yawning,” Martin Schürmann, Maike D. Hesse, Klaas E. Stephan, Miiamaaria Saarela, Karl Zilles, Riitta Hari and Gereon R. Fink, NeuroImage, in press, January 2005. The authors, who variously are at Helsinki
University of Technology, Espoo, Finland, and at several institutions in Germany, explain that:
[W]e studied brain activation with functional magnetic resonance imaging (fMRI) while subjects watched videotaped yawns.
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This article is republished with permission from the January-February 2005 issue of the Annals of Improbable Research. You can purchase back issues of the magazine or subscribe to receive future issues, in printed or in ebook form. Or get a subscription for someone as a gift! Visit their website for more research that makes people LAUGH and then THINK.