Stacy A. Wetmore

Butler University | BU · Department of Psychology

Research on primary confessions has demonstrated that it is a powerful form of evidence. The goal of the current research was to investigate whether secondary confessions – the suspect confesses to another individual who in turn then reports the confession to the police – could be as persuasive. In Experiments 1 and 2, participants read a murder tr...

Showups–when a single suspect is presented to an eyewitness–are thought to be a more suggestive procedure than traditional lineups by the U.S. Supreme Court and social science researchers. The present experiment examined the impact of retention interval on showup identifications, because immediate showups might be no worse than, and perhaps even be...

Showups, a single suspect identification, are thought to be a more suggestive procedure than traditional lineups by the U.S. Supreme Court and social science researchers. Previous research typically finds that a clothing match in showup identifications increases false identifications. However, these experiments do not allow for a determination of w...

The present study investigated the impact of a defendant explicitly countering the claim of a jailhouse informant that the defendant confessed to a murder. Jury-eligible community members (N = 127) recruited from Amazon’s Mechanical Turk read (via Qualtrics) a fictional trial summary in which a defendant was accused of murder. The trial was present...

Recent research shows a strong positive relationship between eyewitness confidence and identification accuracy, assuming the confidence judgment results from a first, fair test of memory. The current study examines whether jurors understand this relationship, and the boundary conditions under which this understanding holds. Mock jurors read a trial...

Jailhouse informants are thought to be one of the leading causes of wrongful convictions. The current studies examined community members’ (E1: N = 99; E2: N = 289) willingness to provide false testimony as a jailhouse informant. In E1, participants were all presented a first offer (1-year sentence reduction) to testify as a jailhouse informant. Tho...

Research has demonstrated that primary confessions corrupt perceptions of forensic evidence, such as handwriting evidence. Additionally, research on secondary confessions indicates that statements made by jailhouse informants influenced juror decision making to the same degree as primary confessions. The goal of the current study was to investigate...

This study investigated the impact of jailhouse informant (JI) testimony on mock-jurors’ perceptions of an alcohol-facilitated rape trial. Male and female participants (N = 186) read a rape trial summary of an adult female after attending a concert. The trial varied whether the victim was intoxicated or sober and whether a JI testified that the def...

This chapter explores an emerging area of psychology and law: informant witnesses. Since the introduction of plea-bargained testimony, informant witnesses have come forward with information that has led to wrongful convictions. An informant witness can be an accomplice witness, who, through their own admission, has participated in a crime and is wi...

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...

The present study examined the presence of a jailhouse informant (JI) on mock jurors’ perceptions of a sexual assault trial. In two experiments, male and female, jury-eligible community members (recruited from Amazon’s Mechanical Turk) read (via Qualtrics) a fictional trial summary in which a defendant sexually assaulted a 6-year-old child or 25-ye...

Informant testimony is a leading cause of wrongful convictions. The Supreme Court has recognized the questionable reliability of informant testimony but has generally held it admissible while emphasizing the existing safeguards built into the legal system. Psycholegal research has demonstrated the overwhelmingly persuasive nature of informant testi...

Jailhouse informants are a leading cause of wrongful convictions. In an attempt to preempt such miscarriages of justice, several states (e.g., Connecticut and California) have mandated that judicial instructions be provided to act as a safeguard against false testimony. This study evaluated the effectiveness of these instructions in helping jurors...

The present study explored whether the successful detection of a jailhouse informant's ulterior motives, inconsistencies in testimony, and knowledge of privileged crime details would influence verdict decisions. Undergraduate participants (N = 381, 218 females) listened to a trial transcript in which a jailhouse informant's testimony was manipulate...

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 US and UK lineup procedures, discriminability and reliability was better when memory was tested using the US procedure. However, because there are so many differences between the procedur...

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 US and UK lineup procedures, discriminability and reliability was better when memory was tested using the US procedure. However, because there are so many differences between the procedur...

Prior research has shown that primary confession evidence can alter eyewitnesses’ identifications and self-reported confidence. The present study investigated whether secondary confession evidence from a jailhouse informant could have the same effect. Participants (N = 368) watched a video of an armed robbery and made an identification decision fro...

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 (o...

Lampinen (2016) suggested that proponents of ROC analysis may prefer that approach to the diagnosticity ratio because they are under the impression that it provides a theoretical measure of underlying discriminability (d′). In truth, we and others prefer ROC analysis for applied purposes because it provides an atheoretical measure of empirical disc...

From the perspective of signal detection theory, different lineup instructions may induce different levels of response bias. If so, then collecting correct and false identification rates across different instructional conditions will trace out the receiver operating characteristic (ROC)—the same ROC that, theoretically, could also be traced out fro...

We surveyed students, community members, and defense attorneys regarding beliefs about secondary confession evidence (i.e., when a third party tells authorities that a person has confessed to him or her) from jailhouse informants and other sources. Results indicated that laypeople perceive secondary confessions as less credible than other types of...

This study examined the effects of post-identification feedback on witness retrospective self-reports in showups and lineups, and importantly, focused on guilty and innocent suspect identifications. After viewing a mock crime video, participants were asked to identify the suspect from either a target-present or target-absent photo lineup or showup....

The U.S. Supreme Court, state courts, and social science researchers have stated that showup identifications (one-person identifications) are less reliable than lineup identifications. Moreover, 74 % of eyewitness experts endorsed false identifications as more likely to occur from showups than lineups. Examination of the extant literature and recei...

We investigated the impact of filler quality and presence on confidence, response latency, and propensity to respond ‘don't know’ in eyewitness line-ups and showups. More specifically, we tested the hypothesis that confident, fast witnesses would be accurate in fair line-ups and showups, but the inclusion of duds (poor fillers) would break down the...

Feedback provided to eyewitnesses can influence memory for how confident their previous lineup selections were. Witnesses given confirming feedback remember being more confident than witnesses who are told their selection was incorrect regardless of their accuracy. This can have a powerful impact on judges and juries. In the current paper, we exami...

Previous research reveals that showups are an inferior eyewitness identification procedure to lineups, but no single study has compared younger and older adults’ identification decisions for both of these procedures. We had witnesses watch a mock crime video and then make an identification decision from a fair lineup, a biased lineup, or a showup t...

Memory is a reconstructive process, relying on pre-existing shared knowledge to help us comprehend and interpret what we experience. A reliance on prior knowledge is a vital aid to communication and comprehension, but, as a consequence, results in the modification of some details in an event, the addition of other details, or even the fabrication o...

Showups (a one-person identification) were compared to both simultaneous and sequential lineups that varied in lineup fairness and the position of the suspect in the lineup. We reanalyzed data from a study by Gronlund, Carlson, Dailey, and Goodsell (2009), which included simultaneous and sequential lineups, and using the same stimuli and procedures...

Two experiments examined two potential safeguards intended to protect accused persons against unreliable testimony from cooperating witnesses. Participants in both experiments read a trial transcript where secondary confession evidence was presented from either a jailhouse informant (Experiment 1 and 2) or an accomplice witness (Experiment 2). In E...

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 line...