Psychophysiological Assessment of Social Stress in Natural and Laboratory Situations

Abstract. Experience sampling and psychophysiological ambulant assessment methods were employed to compare reactions to social stress using a laboratory stressor (The Trier Social Stress Test [TSST]) or a corresponding real-life condition (seminar presentation). Stress reactions were assessed by self-report as well as additional heart rate (AHR, i.e., heart rate increases corrected for physical activity and initial values) and were compared to a control condition in each group. Twenty-five participants gave a talk in a university seminar course and twenty-two participants took part in the TSST. The TSST elicited a greater overall physiological stress reaction as compared to the seminar presentation. However, analyses of dynamic AHR levels revealed that the groups of speakers showed different response profiles during the time course of the stress situations. AHR levels of both groups were similar at the beginning of the free speech. During the course of their presentation, seminar speakers downregulated their arousal level. The arousal level of TSST participants showed a further increase in the later portion of the TSST during the mental arithmetic task. Thus, the more prominent overall physiological stress reaction during the TSST as compared to the seminar presentation appeared to depend on different demand characteristics rather than on differences of laboratory versus real-life situations per se. The experience of emotional strain was greater in response to the social stressors than in response to control situations in both the TSST and seminar speaker group with no differential effects of the experimental setting (laboratory vs. real life). During the TSST procedure, salivary cortisol concentrations were also assessed. Significant correlations of AHR with cortisol level and subjective experience indicate that AHR measurement provides a valid psychophysiological indicator of social stress. These findings suggest that ambulatory assessment techniques successfully contribute to the validation of a common social stress task.