اثر جذابیت فیزیکی ادراک شده بر روی صفحه نمایش صورت زنان و عاطفه

This study used facial electromyographic (EMG) techniques to investigate the effects of perceived physical attractiveness of a target on female viewers' facial muscle activity and self-reported emotion. Female subjects viewed slides of adult males and females that varied in attractiveness. When these female subjects viewed same-sex stimuli, the highly attractive targets evoked greater mean corrugator muscle (brow lowering muscle) EMG and greater reported arousal than the less attractive targets, while reported pleasure was not affected by perceptions of same-sex-stimulus attractiveness. When the female subjects viewed males, ratings of felt pleasure, arousal, and to a lesser extent zygomatic EMG were all greater in response to the highly attractive males than the less attractive. The greater corrugator EMG to highly attractive same-sex targets is interpreted as evidence of a defensive reaction to viewing a high-status competitor, and several explanations for the lack of a self-reported increase in negative affect to these targets are considered.

Since Darwin (1872), human facial display has been thought to be both a reflection of the individual's current emotional state and a means of communicating social and emotional information. In the social negotiation process that occurs when people first meet, cues about the other's social status, dominance standing, and mate potential should be particularly important variables that influence the receiver's behavior and emotions, and specifically his or her facial displays. One individual characteristic that has been found to be associated with perceptions of social success, social competence, and mate potential is physical attractiveness Bassili 1981, Buss 1989, Dion 1986 and Eagly et al. 1991. If physical attractiveness is the most important characteristic that males use for evaluating the mate potential of females Buss 1989, Buss and Schmitt 1993 and Singh 1993, then females' perceptions of the physical attractiveness of other females should reflect their significance as competitors, promote intrasexual competition, and probably result in critical self-comparison and altered mood. There is some evidence for such effects. Viewing pictures of attractive opposite sex individuals has been found to result in greater reported pleasant affect Kenrick et al. 1993 and Lang et al. 1993, whereas viewing attractive same-sex pictures has been found to result in lowered reported mood (Kenrick et al., 1993) and lowered self-ratings of attractiveness in females (Cash et al., 1983). Also, highly physically attractive people were found to be more likely than less attractive people to be rejected by peers of the same sex (Krebs and Adinolfi, 1975), suggesting that same-sex attractiveness can evoke a defensive or competitive response. The facial muscle activity that underlies changes in facial expressions seems a particularly promising behavior to study in investigations of the effects of physical attractiveness. Facial displays have been described as lying along a continuum from behavior that is more or less purely expressive of emotion to behavior concerned primarily with a process of social negotiation or communication Hinde 1985 and Kraut and Johnston 1979. Like other animal displays, facial expressions have evolved to communicate information about the probable future behavior of the displaying individual (Andrew, 1963). For example, eyebrow lowering, which involves the corrugator muscle, has evolved into one component of the threat display used by many primate species, including humans, in conflicts over social dominance standing Andrew 1963 and Ohman 1986. Zygomatic activity during smiling in response to pleasurable stimuli seems to have originated as part of vocalization and laughter, and the infant's smile is selectively directed at the mother from an early age (Andrew, 1963). Electromyographic (EMG) techniques have been found to provide a sensitive and precise measurement of facial muscle activity, and facial EMG is capable of measuring facial muscle activity to weakly evocative emotional stimuli even when no changes in facial displays are detectable by an observer (Cacioppo et al., 1986). Facial EMG activity has been found to be related to several factors. First, a number of studies using various emotional stimuli have demonstrated that corrugator EMG activity varies inversely with the pleasantness (emotional valence) of presented stimuli and is positively related to reports of negative mood state, whereas zygomatic (smile) EMG activity has been found to be positively (albeit less strongly) associated with pleasant emotional stimuli and positive mood state Cacioppo et al. 1986, Dimberg 1982, Dimberg 1986, Dimberg 1990, Lang et al. 1993, Sirota and Schwartz 1982 and Witvliet and Vrana 1995. Not only has it been demonstrated that emotional stimuli lead to characteristic EMG changes, but EMG changes, at least for the corrugator muscle, can predict emotional state (Cacioppo et al., 1988). Other factors besides emotional state also affect these EMG measures. Pope and Smith (1994) found that motivational incongruence and perceived obstacles were specifically predictive of corrugator activity, while subjective pleasantness significantly predicted zygomatic activity. Fridlund (1991) and Fridlund et al. (1992) demonstrated that both real and imagined audiences can have an augmenting effect on both positive and negative emotion facial displays. Hess et al. (1995) demonstrated that emotional state, social context, and the expressor-audience relationship can all affect the intensity of facial displays. Zygomatic activity is not always associated with felt emotion, for the zygomatic muscle also is recruited during fake social smiles and the appeasement smiles of embarrassment Ekman and Friesen 1982 and Ekman et al. 1988, as well as in grimacing in response to shocking and repelling scenes (Lang et al., 1993). Thus, although single facial muscle actions reflect mood or emotional state, they do not convey unequivocal information about specific emotions. In summary, emotional, social, and motivational factors have been found to influence facial muscle activity, and, as Tassinary and Cacioppo (1992) concluded after reviewing facial EMG research, facial muscle activity has multiple determinants. Studies of facial EMG have investigated variations in response to human stimuli as a function of sex, expressions of affect Bradley et al. 1992 and Lang et al. 1993, and race (Vanman and Ito, 1996), but effects of a target's physical attractiveness have not previously been investigated. The objective of this preliminary study was to extend the investigation of social influences on facial displays and emotion by manipulating a socially meaningful dimension of the evocative stimulus while measuring the perceiver's facial EMG and self-reported emotional responses. Slides of adult men and women were presented, along with a sampling of slides of other stimuli, such as nature scenes, food, children, mutilated faces, etc., chosen to tap a wide range of emotional valence and intensity. The male and female slides varied in rated attractiveness from neutral to very attractive. Only female subjects were used in this preliminary study because they have been found to be more facially expressive to emotional stimuli than males (Lang et al., 1993). This experimental situation was considered to be a laboratory analogue of the visual component of an initial human encounter. We predicted that both facial EMG responses and self-reported affect would vary as a function of both the attractiveness and the sex of the stimulus target. We expected corrugator EMG activity of female subjects to be greater when female targets are highly attractive, reflecting both the social communication of defense or threat and an internal process indicative of the perception of a problem or obstacle and associated negative affect. We expected zygomatic EMG activity of female subjects to be greater when male targets are highly attractive, reflecting smiling that might both signal approachability to an attractive male and reflect positive felt emotion. The self-reported emotions were expected to follow similar patterns and thus to replicate previous findings: greater negative affect when viewing more attractive same-sex targets, and greater pleasant affect when viewing more attractive opposite-sex targets Kenrick et al. 1993 and Lang et al. 1993.