It has recently been argued that high-confidence eyewitness identifications are highly likely to be accurate regardless of the quality of viewing conditions experienced by the witness. However, new evidence suggests that evaluators of eyewitness identification evidence (e.g., jurors) do not trust highly confident eyewitnesses who experienced poor witnessing conditions. In fact, contextual information about poor witnessing conditions decreases evaluators’ belief of eyewitnesses to a greater extent for highly confident witnesses than for moderately confident witnesses. Why is the effect of witnessing-condition information greater for evaluations of high-confidence witnesses than for less confident witnesses? The current research tested the possibility that information about witnessing conditions influences evaluators’ perceptions of how well-calibrated a witness’s identification confidence is with the eyewitness’s accuracy. Using a paradigm adapted from the confidence calibration literature, I conducted an experiment to test this calibration account of the finding that witnessing condition information has a stronger effect on perceptions of highly confident witnesses than moderately confident witnesses. Although the results replicated the differential effects of witnessing condition context on perceptions of highly and moderately confident eyewitnesses, they failed to yield support for the confidence calibration hypothesis, potentially because the confidence calibration manipulation was ineffective. Directions for future research are discussed.

The purpose of this thesis is to examine the available literature on suspect bias in the context of general impairment to evaluate support for the claim that general impairment exacerbates the effect of suspect bias to increase the risk of eyewitness misidentifications. To provide context for the importance of this issue, the misidentification of Ronald Cotton in the investigation of the assault of Jennifer Thompson-Cannino is discussed. I identified meta-analyses discussing the following suspect bias variables: prior mugshot exposure, exposure to composites, suspect-filler similarity, post-identification feedback, and the use of showups versus lineups to evaluate the literature. Using the articles citing the meta-analyses and cited within the meta-analyses, I found individual studies that manipulated suspect bias, in addition to a general impairment variable. Examples of general impairment variables include age, time delay, lineup presentation, lineup instructions, and options for identification responses. For each suspect-bias variable discussed, the literature provided inconsistent results. Based on the variations found in the data that was evaluated, I recommend that further examination of suspect-bias in the context of general impairment variables be conducted to garner a better, more cohesive understanding of the interaction between these variables.