Yawning is characterized by gaping of
the mouth that is accompanied by a long
inspiration foflowed by a shorter expiration.
Yawning is a behavior of the type called
-stereotyped- or -fixed- by ethologists and is
triggered by yet unspecified physiological
states or -released- by witnessing yawns or
yawn-related stimuli (Provine, 1986). Indeed,
yawning may be the best example of a stereotyped
action pattern and stimulus releaser in humans.
Yawning is an obvious, common, and probably
universal human act that is performed throughout
the lifespan; however, there is much opinion but
little empirical evidence concerning why yawning
occurs, what function yawning serves, and what
environmental circumstances modulate yawning
rate (Barbizet, 1958; Heusner, 1946; Provine,
1986). For example, the association of yawning
with low levels of arousal (Kataoka, 1975;
Kishida, 1973,Sakai & Takahashi, 1975) has
led to speculation about the role of yawning in
increasing alertness. It also is commonly
believed that more yawning occurs while
observing uninteresting than interesting events.
This may be the basis for the recognition of the
yawn as a paralinguistic signal for boredom. The
popular press acknowledges that the yawn is a
sign of boredom by referring to boring speeches
and uninspiring artistic or sports events as
yawners.
The present study evaluated the hypothesis
that subjects yawn more while observing
uninteresting than while observing interesting
stimuli by comparing the yawns produced to two
stimuli that differed in interest. Subjects
viewed either a 30-min videotape of rock videos,
an interesting and complex visual and auditory
stimulus for most college students, or a 30-min
videotape of an unchanging color-bar test
pattern that had no audio channel, a very
uninteresting stimulus.
METHOD
Subjects : Thirty-two subjects (16
males and 16 fernales), mostly college freshmen
between 17 and 19 years of age, volunteered to
earn experiment participation credit in an
introductory psychology class.
Procedure : Subjects participated in
two experimental sessions that were scheduled at
least 2 days apart. In Session 1, each subject
viewed either a 30-min videotape of rock and
popular music performances, a complex
audiovisual stimulus of interest to most coflege
students, or an unchanging 30-min color-bar test
pattern that had no audio channel, a very
uninteresting stimulus. In Session 2, each
subject viewed the stimulus not presented to
him/her during Session 1. The order of stimulus
presentation was counterbalanced. Subjects were
tested individually.
Subjects were seated behind a desk in a
small, sound-attenuated room (floor dimensions
2.5 X 3. 1 in) and were told to observe a video
monitor screen (53 cm diagonal) that was
approximately 1.5 in distant. Instructions were
provided by the monitor via videotape by a
college-age fernale. Subjects were told to
record your yawns, if any should occur, by
pressing the button on the box on the table in
front of you. Press the button when you inhale
at the start of a yawn and keep the button
depressed until you finish exhaling at the end
of a yawn. You will be recording your own
activity. During a session, you will not be
observed in any way.
Subjects were then shown one of the two
30-min stimulus tapes. Subjects' self-reported
yawning responses were recorded with an
EsterlineAngus event recorder. The present
instructions to subjects were briefer than those
used previously (Provine, 1986) because
extensive instructions may contain a variety of
yawn-related stimuli capable of evoking yawns
that can obscure between-group
différences. The abbreviated instructions
may reduce the precision of the measurement of
yawn duration, but will not affect the
measurement of the variable of primary interest,
yawning frequency.
RESULTS
Subjects viewing the color-bar test pattern
without an audio track performed significantly
more yawns than those viewing the music video
[mean = 5.78 vs. 3.41, F(1,28) = 4.26, p
< .051. For the small subset of 14 of the 32
subjects who yawned in both conditions and for
whorn it was, therefore, possible to compare
yawn duration, viewers of the test pattern
performed longer yawns than viewers of the music
video [mean = 3.79 vs. 3.05 sec,ffl, 10) =
5.39, p < .051. Neither gender nor the order
of conditions had any effect on yawn frequency,
but there was a gender différence for
yawn duration. For males the duration was 4.05
sec, whereas for fernales it was 2.95 sec
[ffl,10) = 7.59, p < .021.
DISCUSSION
The present analysis confirms the folk belief
that people yawn more during uninteresting than
interesting events. A positive correlation
between yawning and the drowsiness experienced
immediately before and after sleeping is
reported elsewhere (Provine, Hamernik, &
Curchack, 1986). Taken together, these results
for stimulus interest and sleeping times provide
empirical support for the recognition of the
yawn as a paralinguistic signal for drowsiness,
fatigue, disinterest, and boredom. Yawning
frequency and duration were both less in the
interesting than in the uninteresting stimulus
condition. As previously shown, yawns may be
performed ai rates ranging from zero to several
yawns per minute (Provine, 1986). However, the
yawn is a stereotyped action pattern that is
performed ai so-called -typical intensity";
extremely short or fractional yawns are seldom,
if ever, produced (Provine, 1986). Although
there are more constraints on the duration than
the frequency of yawns, the present finding of
shorter yawns by observers of interesting
stimuli suggests that there is ai least modest
context-induced variability in yawn duration. A
gender différence in yawn duration was
also detected; males performed longer yawns than
females. The relatively short yawns reported by
all groups in the present study may be due to
the shorter than usual training and instruction
of subjects (cf. Provine, 1986), a modification
of procedure that was made to reduce the
probability of indirectly priming the yawning
response (see Method). Future analyses of yawn
duration should use direct measures of the
inspiration and expiration of yawns or videotape
analyses of yawn movements to avoid possible
confounds that may bc attributable to the
self-report procedure. For example, subjects may
concentrate more on interesting than on
uninteresting stimuli and, thus distracted,
report but not perform shorter yawns. These
concerns about the self-report of yawn duration
are not relevant to the measurement of yawn
frequency, the variable of principal concern in
the present study.
REFERENCES
- BARBIZET,
L (1958). Yawning. Journal of Neurological &
Neurosurgical Psychiatry, 21, 203-209.
- HEUSNER, A. P.
(1946). Yawning and associated phenomena.
Physiological Review, 25, 156-168.
- KATAOKA, J. (1975). Free physical movements
during waiting while standing and sitting.
Journal of Hunuin Ergology, 4, 3-13.
- KISHIDA, K. (1973). Temporal change of
subsidiary behavior in monotonous work. Journal
ofHuman Ergology, 2, 75-89.
- PROVINE, R. R. (1986). Yawning as a
stereotyped action pattern and releasing
stimulus. Ethology, 72, 109-122.
- PROVINE, R. R., HAMERNIK, H. B., &
CURCHACK, B. C. (1986). Yawni . ng, stretching,
and sleeping. Unpublished manuscript.
- SAKAI K., TAKAHASHI, Y. (1975). Driving and
subsidiary behavior of taxi drivers working
alternate day shifts. Journal of Human Ergology,
4, 115-127.
 
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