The Effects of Stress on Group Decision-Making and Group Judgment

• Applicants: Professor Dr. Jan A. Häusser; Professor Dr. Andreas Mojzisch
• Subject Area: Social Psychology, Industrial and Organisational Psychology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 549868045

Whereas there is a rich body of studies examining the effects of stress on individual decision-making and judgment, there is yet no convincing research regarding the effects of stress on group decision-making and group judgment. The proposed research project aims at filling this gap. We present a new theoretical model that builds on biopsychological research on how stress affects information processing at the individual level. The key idea of our theoretical model is that stress causes a shift from an information-driven discussion style to a preference-driven discussion style. That is, when under stress, group members should be more inclined to simply exchange and combine their opinions, rather than exchanging relevant information before making a final group decision or group judgment. This stress-induced preference-driven discussion style, in turn, should have a negative effect on group decision quality and group judgment accuracy. We derive six hypotheses from our model specifying how stress should unfold its negative effects on group decision-making and group judgment. All hypotheses will be preregistered. Study 1 will examine the effects of stress on group decision-making, while Study 2 will examine the effect of stress on group judgment. To test the key hypothesis of our model that a preference-driven discussion style mediates the effects of stress on group decision and group judgment quality, we will use an experimental-causal-chain design in both studies. In stark contrast to the commonly used measurement-of-mediation design, experimental-causal-chain designs allow for clear-cut causal inferences. Following standard procedures in experimental stress research, in both studies, stress will be experimentally induced using a newly developed version of the Trier Social Stress Test for Groups (TSST-G, von Dawans et al., 2011). In the control conditions, we will use the group version of the Placebo-TSST. In general, the proposed research integrates two lines of studies: social psychological research on group discussion styles and biopsychological research on the effects of stress on cognitive processes involved in individual decision-making and judgment. The proposed research substantially contributes to both fields of studies: Group research has yet widely neglected stress, although it is a highly prevalent and relevant context variable. With regard to biopsychological stress research, our proposed research extends previous research by introducing a social context beyond dyadic interactions.

• DFG Programme: Research Grants