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 ( http://dx.doi.org/10.1016/0031-9384(95)02014-4). 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 (http://www.ncbi.nlm.nih.gov/pubmed/2623064). 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.
(That’s an excerpt from the article “Experiments in Yawning,” Published in AIR 11:1.)