Eyewitnesses’ Pre-lineup Memory Strength Inferences Can Influence Identification Decisions

The potential influence of eyewitnesses’ metacognitions on identification decisions when confronted with a police lineup is largely unexplored. In two experiments, we investigated whether eyewitnesses’ pre-lineup memory strength inferences influenced the likelihood of their choosing from a lineup. In experiment 1, manipulating witnesses’ memory strength inferences, while holding memory encoding and retention conditions constant, increased positive identifications from culprit-absent lineups when witnesses inferred they had a poor memory for the culprit. In experiment 2, witnesses who had been interviewed and experienced difficult rather than easy recall of the culprit that was likely suggestive of a poor memory made more positive identifications from both culprit-absent and culprit-present lineups than those who experienced easy recall. Signal detection analyses supported a criterion shift account that proposes that witnesses who infer they have a relatively poor memory may demand less evidence for a positive identification than if they inferred a good memory. Thus, witnesses’ memory strength inferences may influence identification decisions independent of encoding conditions and lineup characteristics.