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 mise à jour du
21 mars 2002
 Physiol Behavior
 Field observations of yawning
and activity in Humans
Ronald Baenninger, Sue Binkley, Maryann Baenninger
Department of psychology and biology, Temple University, Philadelphia
On yawning and its function
Yawning: an evolutionary perspective
Yawning is a common behavioral act in a wide variety of vertebrate species but its functions are not well understood. Despite the widely held beliefs that it serves as a signal of boredom, results from a lack of oxygen, and that it is a socially contagious act we lack a comprehensive, satisfactory explanation of its mechanisms and functions. Yawning may serve different functions in the variety of species in which it has been observed (2).

In some mammalian species yawning appears to be associated with transitions between periods of high and low activity or arousal (15). Relatively sedentary species that sleep very little, such as many herbivores, apparently yawn infrequently if at all (4); species that sleep 8 or 10 h daily and that altemate between active and inactive periods (e.g., predatory carnivores and primates) yawn much more frequently (2). Arousal of a sexual nature is associated with yawning in several species of nonhuman primates and rodents; a syndrome of yawning and penile erection has been examined in detail (12). The syndrome is released by several steroid hormones, including testosterone, although little bas been discovered about possible reasons for such an association.

A circadian pattern has been found in spontaneous yawning by rats (1), with the highest frequency being evident during daily transitions between light and dark-. In normal, unstressed humans daily peaks of yawning are also associated with transitions from sleeping to waking and from waking to sleeping (9,13).

Although clear differences exist between individual humans, their daily rhythms of activity are remarkably consistent across long time periods when measured with monitors on the wrist if regular circadian patterns of yawning exist in individuals reasoned that such patterns might be related to such circadian patterns of overall activity. We undertook the first of these studies to examine both activity and yawning patterns in the daily activities of busy adult professionals, and to determine whether any relationships between those patterns could be found in general, or in individuals. For several scientific reasons it was necessary to study subjects outside the laboratory. First, yawning is a low-frequency act, and human subjects cannot be held captive until they yawn often enoug-h to allow statistical analysis. Second, human subjects actively inhibit their yawns when under observation in the laboratory (3,7) so that the apparent objectivity of the laboratory context may result in inaccurate data. Third, our interest was in the natural yawning and activity patterns of people in their daily lives. Previous research has established that self-reports of yawing are valid measures (7) and that interested volunteer subjects can reliably report on their own yawning by keeping loggs (9, 13)

Our working hypothesis has been that yawning is associated with activity (and perhaps arousal) levels in humans and other species (2, 8, 9). According to this hypothesis, we would expect yawning frequency to increase when an individual's activity or arousal level is low and when the environment has not been particularly stimulating, but where vigilance or alertress is necessary. Under these circumstances we would expect increased yawning if our hypothesis is correct; in our view yawning is one means of changing arousal level, and a sign or marker that such a change is occurring. Wrist activity has been used to measure circadian activity rhythms in free-living human subjects. [...]

General discussion : While the small number of subjects in the first study may limit the generality of our findings, both the yawning frequency and activity rythms of individual subjects were clear and quite consistent, and yawn frequencies were similar to those in the second study.

There did appear to be a simple relationship between yawning and activity of individuals as measured by wrist monitors. The increased occurrence of yawning reliably predicted periods of elevated activity in all of the eight records. This close temporal relationship between increased yawning and increased activity held true even in the most active subject, even though this active individual also yawned the least. That the most active subject yawned least is not damaging to our arousal hypothesis because her low frequency of yawning may have been a result of her already having a high level of arousal. While yawning is reliably followed by elevated activity, it does not follow (and our hypothesis does not require) that elevated activity is always preceded by yawning. Yawning is surely only one means of regulating arousal and activity; it may well be a marker of changed arousal level rather than a cause.

Our preliminary findings presented here support previous findings which suggest that yawning is associated with changes in an individual's activity or arousal level. In nonhuman primates yawning (and penile erection) appears in sexual and agonistic contexts (10,15). Yawning may be associated with conflict and stress (11) and is likely when transitions occur between activity or excitation levels (15). Perhaps the common element in these apparently disparate stimulus situations is that yawning is associated with increases in the arousal, vigilance or attentiveness that his important in such situations.

In the second experiment daily rhythm parameters (e.g., wake-up time, to-sleep time) were similar te, those previously reported for university students (5). In this study, as in the firstthe mean daily frequency of yawning was between 7 and 8, but with a range from 0 to 28. 'Mese data are also comparable to those found in earlier studies (9,13). We also confirmed the result (14) that no sex difference in yawning exists in humans. Among nonhuman primates males typically yawn more frequently than females, perhaps as a consequence of more frequent aggonistic activity (12).

Daily frequency of yawning by the undergraduates was not related to times of either waking up or going to sleep. This finding confirms the result (3) that there was no correlation between number of yawns emitted and the duration of sleep the previous night. In the present study more time was spent sleepine on weekends than during the week, while yawning was more frequent during the week than on weekends.

We can only speculate about how our subjects spent their days since we did not ask them to keep legs of their precise activities, nor what they were doing each time they yawned. The fact that more yawning occurred during the week than on weekends is what our arousal hypothesis would predict if subjects engaged in tasks that varied in their arousal requirements during the week, while spending time on week-ends at a lower, more constant level of arousal. There is also another hypothesis that accounts for the difference: Undergraduate activity logs in an earlier study (9) indicated that students yawned most frequently while sitting in class (21% of yawns), an activity that did not occur on weekends.


  1. Anias J, Holmgren B, Urba-HoImgren RU, Egguibar JR Circadian variation of yawning behavior. Acta Neurobiolog. Exp. 44:179-186, l984
  2. Baenninger R Some comparative aspects of yawning in Betta splendens, Homo sapiens, Panthera leo, and Papio sphinx. J. Comp. Psych. 101:349-354, 1987.
  3. Baenninger R; Greco M. Some antecedents and consequences of yawning. Psychological Record 4l~453-460; 1991.
  4. Barbizet, J.; Yawning. J. Neurol. Neurosurg. Psychiatry 21:203-209, 1958.
  5. Binkley S, Tome MB, Mosher K Weekly phase shifts of rhythms self-reported by almost femal human students in the USA and Spain. Physiol. Behav. 46:423-427; 1989.
  6. Binkley S. Wrist activity in a woman: Daily, weekly, menstrual, lunar, annual cycles? Physiol. Behav. 52:411-421; 1992.
  7. Greco M, Baenninger R Self-report as a valid measure of yawning in the laboratory. Bull. Psychonomic Soc. 27:75-76, 1989.
  8. Greco M,Baenningger R Effects of yawning and related activities on skin conductance and heart rate. Physiol. Behav. 50:1067- 1069; 1991.
  9. Greco M, Baenninger R, Govern J On the context of yawning: When, where and why? Psych. Rec. 43:175-183; 1993.
  10. Hadidian J. Yawning- in an old worid monkey, Macaca nigra. Behaviour 75:133-147, 1980.
  11. Mastripieri D, Schino G,Aureli F, Troisi, A A modest proposal: Displacement activities as an indicator of emotions in primates. Anim. Bchav. 44:967-979; 1992.
  12. Phoenix CH, Chambers KC Sexual behavior in adult gonadectomized female pseudohermaphrodite, fernale, and male rhesus macaques treated with estradiol benzoate and testosterone propionate J. Comp. Physiol. Psychoi. 96;823-833; 1982.
  13. Provine RR, Hamemik HB, Curchack BC Yawning: Relation to sleeping and stretching in humans. Ethologgy 76:152- 160, 1987.
  14. Schino G, Aureli F Do men yawn more than women ? Ethol. Sociobiol. 10:375--378; 1989.
  15. Troisi A, Aureli F, Schino , Rinaldi F, DeAngeli The influence of age, sex, and rank on yawning behavior in two species of macaques (M. facicularis and M. jùscata) Ethology 86:303-3 10; 1990.
  16. Ethological study of yawning in primates Deputte BL

    voir aussi

    Baenninger R, Binkley S, Baenninger M Field observations of yawning and activity in humans.
    Baenninger R On yawning and its functions
    Baenninger R, Greco M Some antecedents and consequences of yawning
    Greco M, Baenninger R On the context of yawning: when, where, and why ?
    Baenninger R Some comparative aspects of yawning in Betta sleepnes, Homo Sapiens, Pantera leo and Papio sphinx
    Is yawning an arousal defense reflex ? Askenasy JJ
    Greco M,Baenningger R Effects of yawning and related activities on skin conductance and heart rate