حالات چهره از احساسات: دیدگاه علوم اعصاب شناختی

Abstract Facial expressions are one example of emotional behavior that illustrate the importance of emotions to both basic survival and social interaction. Basic facial responses to stimuli such as sweet and bitter taste are important for species fitness and governed by simple rules. Even at this basic level, facial responses have communicative value to other species members. During evolution simple facial responses were extended for use in more complex nonverbal communications; the responses are labile. The perception and production of facial expressions are cognitive processes and numerous subcortical and cortical areas contribute to these operations. We suggest that no specific emotion center exists over and above cognitive systems in the brain, and that emotion should not be divorced from cognition.

. Introduction Our view is that the emotions, and facial expression in particular, are adaptive social and communicative tools. In some contexts emotional expressions are species-specific and reflexive, as shown by facial responses by animals and human neonates during taste reactivity tests (Grill & Norgren, 1978; Nowlis, 1977; Steiner, Glaser, Hawilo, & Berridge, 2001). Cognitive mediation is important for emotional experience, and variables such as goals and social context influence emotions (e.g., Lazarus, 1999). Facial expressions serve a communicative role, social context influences facial expression of emotion, and humans use facial expressions to interpret the intentions and goals of others. The complex topographies and social meanings of facial expressions are the result of extended use of simple rule-governed species-specific responses. In this paper, we use the example of facial expression to illustrate these points. The paper is divided into three main sections. The first section describes the hedonic functions of facial expression and how regulatory needs can change the facial response to a stimulus in order to demonstrate that, although facial responses to certain stimuli are innate, those responses are labile and subject to modification. The second section discusses the communicative aspects of facial expression, and how social variables can influence the production of facial expressions, followed by a discussion of the ability to interpret and the propensity to infer intentions of others from facial expression and biological movement. The third section presents how neural systems are implicated in emotional behavior and facial perception. The ability to communicate and interpret emotion and intentions through facial expression require the complex interaction of cognitive systems.

. Conclusions Rule-governed facial responses to simple stimuli are tied to systems such as gustation, while “high-order” processing of facial stimuli is subsumed by the neurocognitive systems involved in object recognition and motion detection. Even structures that appear linked to a specific emotion, such as the amygdala, are also associated with a greater range of appraisal processes (Adolphs et al., 1999). Areas involved in higher-order production, identification, and interpretation of emotional expression are probably the result of expanded use of previously existing functional areas. Emotional expression and perception are an integral part of human interaction. On one level, emotional expressions are governed by rules and can be elicited using simple stimuli, as in the example of disgust in the presence of bitter tastes. However, humans and other animals also use facial expressions to communicate various types of information to other species members. The expression of fear, disgust, threat, and pleasure is meaningful to the observer. As a neonate matures, simple rule-governed facial responses are modified through interactions with others, and the infant learns to regulate emotional response. The labile nature of specific facial response topographies suggests a recruitment of simple facial actions during evolution to facilitate communication and social interaction among human beings. Presumably, the ability to express and interpret facial displays led to increased fitness and survivability. The abilities to accurately interpret and express emotions through facial actions develop during infancy and childhood. As children mature, they learn to modify their emotional expression in socially-appropriate ways. Detection of intentions and deceit also improves during childhood; conveying and concealing intentions through nonverbal means are part of human interaction, and probably evolved in concert. The development of deception, parallel development of the detection of deception, is sometimes referred to as the evolutionary arms race. The ability to convey and conceal intentions is advantageous; similarly, the ability to comprehend intentions and detect deceit in others is also advantageous (Byrne & Whiten, 1988). We suggest that no specific emotion center exists over and above cognitive systems in the brain, and that emotion should not be divorced from cognition (Dewey, 1894; Lane & Nadel, 2000; Parrott & Sabini, 1989). One argument against studying emotion within the framework of cognitive science is the historical separation of cognition from visceral processes. But, from a neuroscience point of view, the neural systems engaged during various cognitive processes are also engaged while processing various emotional stimuli.