Are eyewitness accounts biased? Evaluating false memories for crimes involving in-group or out-group conflict.

Eyewitness testimony has been shown to be unreliable and susceptible to false memories. Whether eyewitness memory errors are influenced by the victim's group membership (relative to both the eyewitness and perpetrator) is underexplored. The current study used complementary behavioral and neuroimaging approaches to test the hypothesis that intragroup conflict heightens participants' susceptibility to subsequent false memories. Healthy young adults witnessed and later answered questions about events in which the perpetrator and victim were either 1) identified as in-group members relative to each other and the eyewitness, 2) out-group members relative to the eyewitness, but not each other, or 3) out-group members relative to each other (Experiments 1a and 1b). When perpetrators and victims were in-group members (intragroup conflict), participants showed heightened false memory rates. Moreover, false memories increased upon crime realization. Neuroimaging data analysis revealed that salient (as compared to ambiguous) intragroup conflict elicited heightened activation in neural regions associated with resolving cognitive conflict (anterior cingulate cortex; ACC). Increased functional connectivity between the ACC and dorsomedial prefrontal cortex was associated with subsequent false memories (Experiment 2). Results suggest that the social salience of the intragroup conflict may have been associated with participants' increased susceptibility to false memories.