Social stress and performance in human-machine interaction: a neglected research field.

Given the increasing capabilities of highly automated systems, the article argues for a need to address the issue of social stress in human-machine interaction. It suggests a classification system of subordinate concepts found in the research literature under the heading of social stress. A review of the literature revealed a paucity of studies examining the effects of social stressors on performance. In particular, the review showed a shortage of experimental lab-based work, needed to establish clear cause-effect relationships. The article examined the suitability of different social stressors for lab-based research, not only when humans are the source of stress but also in so-called hybrid teams where social stress is caused by machine agents. The review shows that a closer link is needed between the separate literature on social stress and automation. Finally, three mechanisms are proposed that may predict how social stress may affect performance: 'blank-out'-mechanism, 'rumination'-mechanism, and 'increased-motivation'-mechanism. Practitioner summary: Theories of ergonomics and human factors may benefit from better integration of research and theoretical work in the domain of social stress. This is due to the increasing capabilities of machines to induce social stress. Abbreviations: HMI: human-machine interaction; TSST: trier social stress test.