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Open Access Thesis

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Degree Type

Master of Science (M.S.)

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In an effort to protect innocent suspects in police lineups, guidelines tend to encourage conservative responding in eyewitnesses. We challenge that approach, using model predictions from Signal Detection Theory that suggest conservative responding with standard simultaneous lineup procedures is detrimental to gathering information on the guilt or innocence of suspects. Furthermore, we suggest that a different lineup procedure, a ranking lineup, will avoid this loss of information at conservative levels of response bias. These predictions were tested in two experiments that manipulated response conservativeness in terms of instructions to the witness and witness confidence levels. The results suggest that there is strong evidence for the predicted pattern. That is, conservative responding substantially decreases the information value of witness responses in simultaneous lineups, but not ranking lineups. There is even evidence that the informational value of the ranking procedure can overcome a discriminability disadvantage that was unexpectedly observed in Experiment 1. These results have significant implications for policy recommendations in police lineups and suggest that eyewitness researchers need to rethink which procedures best serve the goal of protecting innocent suspects.

First Advisor

Jeffrey Starns

Second Advisor

Andrew Cohen

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Available for download on Thursday, August 01, 2024