Excitatory strength of expressive faces: effects of happy and fear expressions and context on the extinction of a conditioned fear response.

In a recent study, Orr and Lanzetta (1984) showed that the excitatory properties of fear facial expressions previously described (Lanzetta & Orr, 1981; Orr & Lanzetta, 1980) do not depend on associative mechanisms; even in the absence of reinforcement, fear faces intensify the emotional reaction to a previously conditioned stimulus and disrupt extinction of an acquired fear response. In conjunction with the findings on acquisition, the failure to obtain extinction suggests that fear faces have some of the functional properties of "prepared" (fear-relevant) stimuli. In the present study we compared the magnitude of conditioned fear responses to happy and fear faces when a potent danger signal, the shock electrodes, are attached or unattached. If fear faces are functionally analogous to prepared stimuli, then, even in the absence of veridical support for an expectation of shock, they should retain excitatory strength, whereas happy faces should not. The results are consistent with this view of fear expressions. In the absence of reinforcement, and with shock electrodes removed, conditioned fear responses and basal levels of arousal were of greater magnitude for the fear-face condition than for the happy-face condition.

Influence of facial expressions on the classical conditioning of fear.

Previous research has demonstrated that particular facial expressions more readily acquire excitatory strength when paired with a congruent unconditioned stimulus than when paired with an incongruent outcome. The present study extends these findings on the excitatory and inhibitory role of facial expressions by demonstrating that particular facial expressions (fear and happy), when paired with a neutral cue (tone), can influence conditioning to the neutral conditioned stimulus (CS). It was found that subjects who had a fear expression paired with the neutral CS responded more to the fear expression than to the neutral CS, whereas subjects who had a happy expression paired with the neutral CS responded more to the neutral cue than to the happy expression. These findings strongly support predictions from "overshadowing" or "blocking" models of classical conditioning.

Facial expressions of emotion as conditioned stimuli for human autonomic responses.

This investigation tested the hypothesis that congruity of a facial affective expression with an aversive outcome as compared to incongruity of an expression and outcome would result in superior differential conditioning of an autonomic response (skin conductance) to the facial expression. Using a differential conditioning paradigm with slides of fear faces and happy faces as CS+ and CS- or CS- AND CS+, resepctively, the resultant findings are consistent with predictions. Both magnitude and rate of acquisition of the differential conditioned response were greater when a fear expression was reinforced by shock than when a happy expression was reinforced by shock.

Effects of nonverbal dissimulation on emotional experience and autonomic arousal.

Three studies are reported that examine the relationship between the nonverbal display of emotional affect and indices of the emotional state. Subjects were asked either to conceal or to exaggerate the facial display associated with the anticipation and reception of painful shocks that varied in intensity. Both self-reports of shock painfulness and skin conductance measures of emotional response showed significant changes paralleling the changes induced in expressive behavior; that is, the suppression of expressive responses decreased the magnitude of phasic skin conductance changes and subjective reports of painfulness as compared to the free expression or exaggeration of pain-related expressive response. The effects were obtained for shocks of varying intensities and for both male and female subjects. The findings support theories of emotion that assume that expressive responses serve a self-regulatory as well as a social-communicative function, and further suggest that the self-regulation is mediated neurally, rather than via a process of self-attribution. Finally, the results highlight the need for research on dissimulation in social interaction to consider the effects of acting upon the actor, as well as its effects upon the inferences of observers.

Effects of being observed on expressive, subjective, and physiological responses to painful stimuli.

Two experiments explored the effects of observation by another on responses to painful stimuli. It was anticipated that the intensity of pain-related non-verbal expressivity decreases under observation, while indices of arousal (skin conductance and self-report) increase. In Experiment 1, subjects' expressive responses to shock were attenuated when subjects were observed as compared to when they were alone, but the anticipated augmentation of arousal did not occur. Rather, the attenuation of expressive behavior was accompanied by a general decrease in subjective and autonomic responses to the painful stimuli. A second experiment replicated the results of the first study and, in addition, found no evidence for a differential impact of sex of observer on the three measures of arousal. An interpretation is discussed for the effect of observation on expressive behavior and for the relationships observed among expressive, autonomic, and subjective indices of pain.

The facilitative effect of facial expression on the self-generation of emotion.

Twenty-seven female undergraduates completed three tasks: (1) feel four emotions (happiness, sadness, anger, peacefulness); (2) express these emotions, without trying to feel them; and (3) feel and express clearly these four emotions. During each trial subjects pressed a button to indicate when they had reached the required state, and the latency from emotion cue to button press was measured. Heart rate, skin conductance and EMG from four facial sites (brow, cheek, jaw and mouth) were recorded for 15 s before and after the button press and during a baseline period prior to each trial. Self-reports were obtained after each trial. Facial EMG and patterns of autonomic arousal differentiated among the four emotions within each task. Shorter self-generation latency in the Feel-and-Show versus the Feel condition indicated the facilitative effect of facial expression on the self-generation of emotion. Furthermore, the presence of autonomic changes and self-reported affect in the Show condition supports the sufficiency version of the facial feedback hypothesis. The self-generation method employed as an emotion elicitor was shown to reliably induce emotional reactions and is proposed as a useful technique for the elicitation of various emotional states in the laboratory.