The truth about snitches: an archival analysis of informant testimony.

Informants are witnesses who often testify in exchange for an incentive (i.e. jailhouse informant, cooperating witness). Despite the widespread use of informants, little is known about the circumstances surrounding their use at trial. This study content-analyzed trials from 22 DNA exoneration cases involving 53 informants. Because these defendants were exonerated, the prosecution informant testimony is demonstrably false. Informant characteristics including motivation for testifying, criminal history, relationship with the defendant and testimony were coded. Most informants were prosecution jailhouse informants; however, there were also defence jailhouse informants and prosecution cooperating witnesses. Regardless of informant type, most denied receiving an incentive, had criminal histories, were friends/acquaintances of the defendant and had testimonial inconsistencies. In closing statements, attorneys relied on informant testimony by either emphasizing or questioning its reliability. The impact of informant testimony on jurors' decisions is discussed in terms of truth-default theory (TDT), the fundamental attribution error and prosecutorial vouching.

The effect of post-identification feedback, delay, and suspicion on accurate eyewitnesses.

We examined whether post-identification feedback and suspicion affect accurate eyewitnesses. Participants viewed a video event and then made a lineup decision from a target-present photo lineup. Regardless of accuracy, the experimenter either, informed participants that they made a correct lineup decision or gave no information regarding their lineup decision. Immediately following the lineup decision or after a 1-week delay, a second experimenter gave some of the participants who received confirming feedback reason to be suspicious of the confirming feedback. Following immediately after the confirming feedback, accurate witnesses did not demonstrate certainty inflation. However, after a delay accurate witnesses did demonstrate certainty inflation typically associated with confirming feedback. The suspicion manipulation only affected participants' certainty when the confirming feedback created certainty inflation. The results lend support to the accessibility interpretation of the post-identification feedback effect and the erasure interpretation of the suspicion effect.

Designing police lineups to maximize memory performance.

How can lineups be designed to elicit the best achievable memory performance? One step toward that goal is to compare lineup procedures. In a recent comparison of U.S. and U.K. lineup procedures, discriminability and reliability was better when memory was tested using the U.S. procedure. However, because there are so many differences between the procedures, it is unclear what explains this superior performance. The main goal of the current research is, therefore, to systematically isolate the differences between the U.S. and U.K. lineups to determine their effects on discriminability and reliability. In 5 experiments, we compared (a) presentation format: simultaneous versus sequential; (b) stimulus format: photos versus videos; (c) number of views: 1-lap versus 2-lap versus choice in both video and photo lineups; and (d) lineup size: 6- versus 9-lineup members. Most of the comparisons did not show appreciable differences, but one comparison did: simultaneous presentation yielded better discriminability than sequential presentation. If the results replicate, then policymakers should recommend using a simultaneous lineup procedure. Moreover, consistent with previous research, identifications made with high confidence were higher in reliability than identifications made with low confidence. Thus, official lineup protocols should require collecting confidence because of the diagnostic value added. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The impact of fillers on lineup performance.

Filler siphoning theory posits that the presence of fillers (known innocents) in a lineup protects an innocent suspect from being chosen by siphoning choices away from that innocent suspect. This mechanism has been proposed as an explanation for why simultaneous lineups (viewing all lineup members at once) induces better performance than showups (one-person identification procedures). We implemented filler siphoning in a computational model (WITNESS, Clark, Applied Cognitive Psychology 17:629-654, 2003), and explored the impact of the number of fillers (lineup size) and filler quality on simultaneous and sequential lineups (viewing lineups members in sequence), and compared both to showups. In limited situations, we found that filler siphoning can produce a simultaneous lineup performance advantage, but one that is insufficient in magnitude to explain empirical data. However, the magnitude of the empirical simultaneous lineup advantage can be approximated once criterial variability is added to the model. But this modification works by negatively impacting showups rather than promoting more filler siphoning. In sequential lineups, fillers were found to harm performance. Filler siphoning fails to clarify the relationship between simultaneous lineups and sequential lineups or showups. By incorporating constructs like filler siphoning and criterial variability into a computational model, and trying to approximate empirical data, we can sort through explanations of eyewitness decision-making, a prerequisite for policy recommendations.