Evolution and facial action in reflex, social motive, and paralanguage.

Based upon current evolutionary theory and recent laboratory and field data, this paper introduces a behavioral-ecology view of human facial displays that contrasts with previous views of faces as innate, prototypic, "iconic" expressions of fundamental emotions. First, I detail the criteria for establishing genetic and epigenetic contributions to facial behavior. Under these criteria, cross-cultural communality in canonical facial displays implies neither their genetic control nor their fundamental relation to emotion. New findings reestablish phylogenetic continuity by showing that human facial displays and vigilance for them, like their nonhuman counterparts, coevolve in the service of social motives; faces issued in solitude typically reflect imaginary or implicit interaction. Two evolutionary trends are probably involved in shaping facial actions--emancipation of reflexes, and automatization of instrumental acts. Modern conceptions of genetic and cultural evolution, and knowledge about animal signaling, suggest new hypotheses regarding the origins and functions of facial displays. In so doing, they clarify how facial displays relate to reflexion, motive and intention, emotion and psychophysiology, and language and paralanguage.

Relations between tickling and humorous laughter: preliminary support for the Darwin-Hecker hypothesis.

Following hypotheses by Darwin and Hecker on the connection between tickling and humorous laughter, questionnaire data were collected from 100 college students regarding their reported ticklishness and tendencies to laugh and show responses ancillary to laughter. Ticklishness was related to propensities to: (a) giggle, (b) laugh, (c) smile, (d) piloerect, (e) blush, and (f) cry. These findings lend preliminary support for the Darwin-Hecker conjecture that reflexes underlying ticklishness mediate humor. We speculate on possible relations among tickling and humor, and reasons why people laugh and smile when they find things funny.

Visuospatial dysfunction following unilateral brain damage: dissociations in hierarchical and hemispatial analysis.

Unlike the aphasias, visuospatial dysfunction has resisted fractionation into meaningful spared and impaired component functions. In this study, we show that unilateral brain damage results in pronounced dissociations in both hierarchical and hemispatial processing. Patients with left-hemisphere damage showed the greatest impairment in drawing forms at the lower level of hierarchical stimuli presented in right hemispace, whereas patients with right-hemisphere compromise displayed the opposite pattern. We discuss implications of these results for research in visuospatial function and clinical assessment of visuospatial dysfunction.

What can asymmetry and laterality in EMG tell us about the face and brain?

This paper will review the use of the electromyographic (EMG) technique for studying asymmetry and laterality in facial behavior. My discussion will include several issues: (1) a review of the neurology of facial expression with respect to asymmetry/laterality; (2) a compendium of models of cerebral hemispheric participation in emotion and in facial motor control that imply asymmetry-laterality in facial behavior; (3) a summary of facial asymmetry-laterality findings to date; and (4) uses and abuses of EMG techniques in inferring asymmetry-laterality in facial behavior. I conclude with (5) recommendations for future facial asymmetry-laterality research in general.

Effects of alternative control procedures for electromyographic biofeedback relaxation training.

Twenty-four college students participated in a single session of electromyographic (EMG) biofeedback in a comparison of three experimental control procedures commonly employed in biofeedback relaxation training research. One group received contingent EMG biofeedback from the forehead area, and each subject in this group served as his or her own control. Subjects in a second group received noncontingent EMG feedback from a tape recorder but were instructed to use the feedback signal to relax their forehead muscles (single blind). Subjects in a third group received the same auditory feedback as those in the second group but were not told the purpose or source of the feedback stimulus (yoked control). The contingent feedback group showed significantly less EMG activity when compared to the other two groups. However, this group did not exhibit significant EMG level decrements from the beginning to end of the session. This seemingly contradictory finding may have been due to statistically capitalizing on the artifactually high EMG level of the experimental and control groups, although the single-blind and yoked-control groups showed nonsignificant increases across the session. The single-blind group's data had a variance several times larger than the other two groups' variance. Findings are discussed with respect to a "probing" hypothesis as opposed to the previously offered frustration hypothesis. Of the three control procedures, the data suggest the yoked control as the procedure of choice for EMG biofeedback relaxation research.