This study was designed to extend the research evidence concerning the modulating influence of image motion on emotional and attentional responses to stimulus content. More specifically, this experiment examined the influence of a small moving vs. static facial image of a newscaster (i.e., a social stimulus) on emotion-and attention-related subjective and physiological responses and memory performance when viewing financial news messages.
Emotions and Psychophysiology
Emotional responses to media messages have recently received increased attention in the research on mediated communication, given the intimate relationship of emotion with the four primary goals of media messages: to attract attention, to be remembered, to entertain, and to persuade (e.g., Dillard & Wilson, 1993). According to most theorists, emotions are constituted by three aspects or components: subjective feeling, expressive behavior, and physiological arousal; others add motivational state or action tendency and/or cognitive processing (see P.J. Lang, 1995; Scherer, 1993). According to a dimensional theory of emotion, all emotions can be located in a two-dimensional space, as coordinates of valence and arousal (or bodily activation (e.g., P.J. Lang, 1995; Larsen & Diener, 1992). The valence dimension refers to the hedonic quality or pleasantness of an affective experience, and ranges from unpleasant to pleasant. The arousal dimension refers to the level of activation associated with the emotional response, and ranges from very excited or energized at one extreme to very calm or sleepy at the other.
Emotion-related physiological, self-report, and behavioral reactions can be elicited by stimuli in different sensory modalities. Using a paradigm in which stimuli are presented for 6 s (with an interstimulus interval of about 20 s), P. J. Lang and co-workers have shown that both affective (still) pictures and sounds elicit patterns of phasic physiological response that vary systematically as a function of the normative valence and arousal of the stimuli (e.g., Bradley & Lang, 2000a, 2000b; P. J. Lang, Greenwald, Bradley, & Hamm, 1993). Under this paradigm, facial electromyography (EMG) and heart rate (HR) are the primary psychophysiological indices of hedonic valence. That is, EMG activity increases with the contractions of the facial muscle groups responsible for positive and negative emotional expressions. Although, in general, HR decelerates in response to both unpleasant and pleasant pictures, (1) subjects exhibit relatively more HR deceleration when viewing unpleasant pictures as compared to pleasant pictures (e.g., Bradley, Cuthbert, & Lang, 1996; Cuthbert, Bradley, & Lang, 1996). An attentional interpretation of this phenomenon is available, however, given that (a) humans may be hardwired to allocate more attention to negative stimuli compared to positive stimuli to promote survival (e.g., Bradley, 1994), and (b) HR decelerates as a result of increased cardiac parasympathetic activity when attention is paid to an external stimulus (e.g., Lacey & Lacey, 1970). Electrodermal activity (EDA), commonly known as skin conductance, is the primary psychophysiological index of arousal. As people experience arousal their sympathetic nervous system (SNS) is activated, resulting in increased sweat gland activity and skin conductance.
Emotional and Attentional Responses to Presentation Attributes
Evidence has also accumulated that the relationship of stimulus content with emotional and attentional responses, both subjective and physiological, may be modulated by the formal properties of stimulus presentation. For example, Detenber and Reeves (1996) found that a large screen size results in greater self-reported arousal when viewing pictures, but has no significant effect on valence ratings. Likewise, Reeves, Lang, Kim, and Tatar (1999) showed that a large screen evoked greater physiological arousal as indexed by EDA than medium and small screens (56-inch, 13-inch, and 2-inch picture heights, respectively) when viewing 6-s video clips, particularly when the clip content was arousing. …