Subjects will show more cheek EMG activity to positive stimuli when either an implied or actual audience is present compared to times when one is not, but do not report more enjoyment of the stimulus in the audience conditions ( Fridlund, 1991).
For example, increased facial EMG activity at the cheek site does not necessarily mean that the subject consciously is experiencing an increase in positive affect. The use of facial EMG does have limitations, however. Specific waveforms of the EMG response can also index momentary changes in affect while a subject engages in conversation during an interview, even though a trained observer cannot detect such changes in the overt facial expressions ( Cacioppo, Martzke, Petty, & Tassinary, 1988). Thus, facial EMG activity can differentiate the valence and intensity of affective reactions, and is less susceptible to some of the problems associated with traditional self-report measures, such as demand characteristics and concerns about socially desirable responding (cf. Facial EMG activity recorded from the cheek and brow regions distinguishes between mild and moderate positively and negatively valenced stimuli, respectively ( Cacioppo, Petty, Losch, & Kim, 1986). Several researchers (e.g., Fridlund, Schwartz, & Fowler, 1984 McHugo, Smith, & Lanzetta, 1982 Schwartz, Fair, Salt, & Mandel, 1976) have found that the zygomaticus major (the muscle in the cheek that pulls up the lip corner) and the corrugator superala (the muscle above the eye that pushes the brows together) typically exhibit increased activity during times at which the subject later reports having experienced positive or negative affect, respectively, even though the face showed no expression overtly at the time.
In addition, as we mentioned earlier, many emotion theorists emphasize that the role of the face in emotional expression makes it an important source of data about emotion and affect, whether through coding systems of overt facial activity (e.g., Ekman & Friesen, 1978 Izard, 1979) or the measurement of covert facial muscle activity via electromyographic (EMG) recording. Nearly all agree that to measure the emotional experience properly, one must incorporate verbal measures that go beyond simple valence and intensity dimensions and access the quality of distinct emotions (e.g., “fear,” “anger”). Indeed, the ability to measure emotion sets limits on the theoretical questions that can be addressed.ĭespite their differences, there is some agreement between appraisal and biosocial theorists about the measurement of emotion. ERIC J VANMAN, NORMAN MILLER, in Affect, Cognition and Stereotyping, 1993 Emotion MethodologyĪlthough many emotion theories can be applied to intergroup relations, none will be very useful if issues pertaining to the measurement of emotion constructs are not considered.
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