تقلید صورت خود به خودی در پاسخ به حالت پویای صورت
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|37703||2007||18 صفحه PDF||سفارش دهید||6847 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Cognition, Volume 104, Issue 1, July 2007, Pages 1–18
Abstract Based on previous neuroscientific evidence indicating activation of the mirror neuron system in response to dynamic facial actions, we hypothesized that facial mimicry would occur while subjects viewed dynamic facial expressions. To test this hypothesis, dynamic/static facial expressions of anger/happiness were presented using computer-morphing (Experiment 1) and videos (Experiment 2). The subjects’ facial actions were unobtrusively videotaped and blindly coded using Facial Action Coding System [FACS; Ekman, P., & Friesen, W. V. (1978). Facial action coding system. Palo Alto, CA: Consulting Psychologist]. In the dynamic presentations common to both experiments, brow lowering, a prototypical action in angry expressions, occurred more frequently in response to angry expressions than to happy expressions. The pulling of lip corners, a prototypical action in happy expressions, occurred more frequently in response to happy expressions than to angry expressions in dynamic presentations. Additionally, the mean latency of these actions was less than 900 ms after the onset of dynamic changes in facial expression. Naive raters recognized the subjects’ facial reactions as emotional expressions, with the valence corresponding to the dynamic facial expressions that the subjects were viewing. These results indicate that dynamic facial expressions elicit spontaneous and rapid facial mimicry, which functions both as a form of intra-individual processing and as inter-individual communication.
. Introduction Communication through facial expressions of emotion plays an important role in social coordination (Keltner & Kring, 1998). Through the evolutionary process, facial expressions would have helped humans take collective actions during danger and forming intimate relationships with other individuals. Consistent with this idea, psychophysiological studies using facial electromyography (EMG) indicate that facial expressions elicit facial muscular activity congruent with the presented facial expressions. For example, Dimberg (1982) showed that mere photographic presentations of angry and happy facial expressions induced spontaneous corrugator supercilii muscle activity (brow lowering actions, prototypical in angry facial expressions) and zygomatic major muscle activity (lip corner pulling actions, prototypical in happy facial expressions), respectively. This facial muscular activity may be interpretable as mimicking behavior or “facial mimicry” (Hess, Philippot, & Blairy, 1999). Dimberg, Thunberg, and Elmehed (2000) reported that facial EMG activity occurred even without awareness of the specific facial expression, confirming the spontaneous nature of the responses. This facial reaction occurs rapidly; Dimberg and Thunberg (1998) showed that facial EMG activity occurred after only 500 ms of exposure to the facial pictures. These data imply that facial muscle activity that may relate to facial mimicry occurs spontaneously and rapidly in response to facial expressions. However, there is little evidence as to whether the facial muscle activity revealed by EMG recordings is externally visible as facial mimicry. This point is crucial because if overt facial mimicking occurs when perceiving facial expressions of emotion, then this facial motor activity could function not only in intra-individual processing, such as empathic understanding, but also in inter-individual communication. Although developmental studies have demonstrated that neonates exhibit overt facial mimicry of adult facial expressions (Meltzoff and Moore, 1977 and Field et al., 1982), the visibility of facial activity has not been explicitly measured in EMG studies with adult subjects. As these facial EMG amplitude changes are very subtle (a few microvolts), facial muscle activities may not be visible (cf. Cacioppo, Petty, Losch, & Kim, 1986). With regard to the mechanism of facial mimicry, recent neuroscientific evidence provides the clue, pointing to the involvement of motor-related brain areas in social communication. Single-unit recording studies in monkeys have revealed that specific neurons in the ventral premotor cortex (area F5) discharge both when the monkey performs specific hand actions and when it observes experimenters performing similar actions; These neurons have been named “mirror neurons” (Gallese et al., 1996 and Rizzolatti et al., 1996). A recent study with monkeys revealed that the neurons in this region discharge during the observation of communicative facial actions (Ferrari, Gallese, Rizzolatti, & Fogassi, 2003). Neuroimaging studies have confirmed the existence of the mirror neuron system in humans. Buccino and his colleagues (Buccino et al., 2001 and Buccino et al., 2004) showed that observing videotaped mouth actions, as compared to the observation of static faces, activated the ventral premotor area, centered to the pars opercularis of the inferior frontal gyrus of Brodmann area (BA) 44, an area that has been proposed as the human homologue of area F5 (Rizzolatti & Arbib, 1998). A recent neuroimaging study (Sato, Kochiyama, Yoshikawa, Naito, & Matsumura, 2004) extended the notion of the mirror neuron system in humans into the processing of facial expressions of emotion. In this study, brain activity in response to dynamic facial expressions of fear and happiness was compared to activity in response to static expressions and dynamic mosaic images. Results revealed that, in addition to areas such as the temporal cortex, the pars opercularis of the inferior frontal gyrus (BA 44), was more active in response to the dynamic facial expressions than it was to both control stimuli that were common to both expressions. This suggests that the mirror neuron system in the ventral premotor cortex may be automatically activated when processing facial expressions of emotion, especially if the expressions are dynamic. This neuroscientific evidence indicates that the mirror neuron system is specifically involved in the processing of dynamic actions relative to static actions. Such evidence further suggests the possibility that the subtlety of facial reactions indicated in previous facial EMG literature may have been a consequence of using static facial expressions as stimuli in almost all of the studies undertaken to date, with the exception of a few studies such as that conducted by McHugo, Lanzetta, Sullivan, Masters, and Englis (1985). We hypothesized that facial mimicry may evidently occur, in the externally visible form, in response to the dynamic facial expressions of emotion. In the present study, we conducted two experiments to investigate whether spontaneous, externally visible facial mimicry occurs by videotaping subjects’ facial reactions while they were passively observing dynamic or static facial expressions. A video prompter system, an apparatus generally used in television studios, was used to videotape the subjects’ facial reactions. This allowed us to videotape subjects’ facial expressions while they were unaware of the presence of a video camera. To analyze the facial reactions, scorers blindly scored the facial movements using the Facial Action Coding System (FACS; Ekman & Friesen, 1978). Action unit (AU) 4 (brow lowering, prototypical facial actions in angry expressions) and AU 12 (lip corner pulling, prototypical facial actions in happy expressions) were evaluated. To present the dynamic facial expressions, we used the computer-morphing techniques in Experiment 1 and videos of natural facial expressions in Experiment 2 because these methods both have advantage and disadvantages and are complementary to each other (Sato & Yoshikawa, 2004). We prepared facial expressions of anger and happiness to represent positive and negative emotional valence. We used the apex images of the dynamic facial expressions under static conditions. We predicted that specific facial action patterns, interpretable as facial mimicry, would occur spontaneously in dynamic presentations, but not necessarily in static presentations.
نتیجه گیری انگلیسی