In this study, we investigated differences in affective reactivity, the intensity and variability in response to evocative stimuli, along with interoceptive sensitivity, sensitivity to changes in body state. Participants completed experimental tasks while we measured their peripheral physiology, including electrodermal activity, respiration, cardiac activity, and facial electromyography. The first task measured interoceptive sensitivity by asking participants to detect their heartbeat. In the second task, participants viewed negative, positive, and neutral images from the International Affective Picture System (IAPS) and listened to sounds from the International Affective Digitized Sounds (IADS). Participants self-reported reactions to the stimuli on scales of pleasantness and activation. Participants then completed ten questionnaires to assess various aspects of affective reactivity such as emotional control, alexithymia, and body vigilance. The study is ongoing but preliminary evidence indicates significantly greater corrugator supercilii activity for negative stimuli and significantly greater zygomaticus major activity for positive stimuli. The corrugator supercilii muscle is located above the area between the eyebrows, and is considered to be a signifier of negative affect (frowning). The zygomaticus major muscle extends from the cheekbone to the corners of the mouth, and is related to positive affect (smiling). Moreover, participants have a greater number of skin conductance responses (SCRs), a measure of sympathetic nervous system activity, or physiological activation, during high-arousal than low-arousal stimuli. Finally, we demonstrate that individual differences in interoceptive sensitivity are related to differences in affective reactivity which may have implications for treatment of affective disorders.
Presenter: Inbae Choi
PI: Lisa Barrett