Fearing the uncertain: Self-uncertainty plays a role in mortality salience

•Mortality salience increased self-uncertainty when self-esteem was not enhanced.•Mortality salience increased identification when self-esteem was not enhanced.•Reduced uncertainty attenuates the impact of mortality salience on identification.•Reduced uncertainty attenuates the impact of mortality salience on ingroup defense.

Two experiments were conducted to examine the relationship between self-uncertainty, self-esteem and mortality salience as they relate to group identification and defense of the ingroup. Experiment 1 (N = 140) tested the hypothesis that self-uncertainty mediates the interactive effect of self-esteem and mortality salience on group identification. Results demonstrated that mortality salience only increased self-uncertainty and identification under neutral self-esteem, and self-uncertainty mediated the interactive effect of mortality salience and self-esteem on ingroup identification. Experiment 2 (N = 294) tested the hypothesis that only when self-uncertainty is elevated does the interactive effect of self-esteem and mortality salience predict group identification and ingroup defense. As hypothesized, when self-uncertainty was reduced TMT results were attenuated. Results across the two experiments demonstrate that self-uncertainty plays a significant role in reactions to mortality salience.