Identifying unfamiliar voices: the influence of sample duration and parade size.

Voice identification parades can be unreliable due to the error-prone nature of earwitness responses. Home Office guidelines (2003) recommend that voice parades should consist of nine-voices, each played for 60-seconds. This makes parades resource-consuming to construct. In the present paper we conducted two experiments to see if voice parade procedures could be simplified. In Experiment 1, we investigated if reducing the duration of the voice samples on a nine-voice parade would negatively affect performance. In Experiment 2, we first explored if the same sample duration conditions used in Experiment 1 would lead to different outcomes if a six-voice parade were used. Following this, we investigated if there were any difference in identification performance based solely on whether a nine-voice (Experiment 1) or six-voice (Experiment 2) parade was used. Overall, the results suggest that voice durations can be safely reduced without disrupting listener performance. Performance on target-absent parades – which simulate an innocent suspect being apprehended – were at chance-levels in both parade sizes, but the increased number of foils in the nine-voice parade offers increased protection to an innocent suspect by virtue of statistical probability. Thus, we argue that the Home Office guidelines recommending a parade with nine-voices should be maintained.

From Witness to Web Sleuth: Does Citizen Enquiry on Social Media Affect Formal Eyewitness Identification Procedures?

Eyewitnesses to crimes may seek the perpetrator on social media prior to participating in a formal identification procedure, but the effect of this citizen enquiry on the accuracy of eyewitness identification is unclear. The current study used a between-participants design to address this question. Participants viewed a crime video, and after a 1–2-day delay were either exposed to social media including the perpetrator, exposed to social media that substituted an innocent suspect for the perpetrator, or not exposed to social media. Seven days after viewing the crime video, all participants made an identification from a video lineup. It was predicted that exposure to social media that did not contain the guilty suspect would reduce the accuracy of subsequent identifications. Analysis revealed no association between social media exposure and lineup response for target present lineups. For target absent lineups, there was a significant association between social media exposure and lineup response, but this was driven by a higher number of correct rejections for participants who saw the guilty suspect on social media. The results suggest that at least in some circumstances, witnesses searching social media do not have a negative effect on formal ID procedures.

Practical Solutions to Forensic Contextual Bias

In 2009, the National Research Council (NRC) globally criticized forensic science and, in particular, the potential for contextual bias to increase errors in forensic examination. Nevertheless, very few research-based solutions have been proposed and, of the current recommendations, none are consistently used in practice. Two experiments are presented here. Experiment 1 replicates and extends the Quigley-McBride and Wells (2018) study in which fingerprint lineups (the Filler-Control Procedure) were shown to neutralize the effect of contextual information on novice fingerprint evaluations. Experiment 2 demonstrates that restricting the use of evidence lineups to verification decisions would also be effective for reducing incorrect match decisions without straining resources. In both experiments, the filler-control procedure consistently reduced the effect of suggestive contextual information and protected innocent suspect prints from being mistakenly matched to crime samples. Interdisciplinary approaches are discussed as a way to help close the gap between research and forensic science practice.

Eyewitness Identification and Distinctive Features: When Similarity Matters

In four experiments, we investigated theoretical and practical issues around eyewitness identification accuracy and confidence for tattooed suspects. We varied how tattoos were treated in lineups (Experiments 1 and 2) and the match between the suspect’s tattoo the perpetrator’s tattoo (Experiments 3 and 4). We replicated the finding that modifying lineup photographs to prevent a tattooed suspect from standing out mitigates the risk of innocent suspect identifications. We also demonstrated that sequential lineups (cf. simultaneous) do not mitigate the risk of biased lineups when the suspect stands out because of a tattoo. Contrary to previous research in which biased lineups did not impact correct identification rates differentially by lineup type, we found that biased lineups decreased correct identifications in sequential, but not simultaneous, lineups. Additionally, we found that the tattoo worn by an innocent suspect need not be identical to that of the perpetrator—similar placement and designs also inflate innocent suspect identifications, although a tattoo in a different location with a different design protected innocent suspects. Finally, our data indicate that when researching distinctive marks in lineups, researchers should request descriptions from the eyewitness-participants following the mock crime in order to determine whether the witness noticed the distinctive mark.

The impact of sleep on eyewitness identifications

Sleep aids the consolidation of recently acquired memories. Evidence strongly indicates that sleep yields substantial improvements on recognition memory tasks relative to an equivalent period of wake. Despite the known benefits that sleep has on memory, researchers have not yet investigated the impact of sleep on eyewitness identifications. Eyewitnesses to crimes are often presented with a line-up (which is a type of recognition memory test) that contains the suspect (who is innocent or guilty) and fillers (who are known to be innocent). Sleep may enhance the ability to identify the guilty suspect and not identify the innocent suspect (i.e. discriminability). Sleep may also impact reliability (i.e. the likelihood that the identified suspect is guilty). In the current study, we manipulated the presence or the absence of sleep in a forensically relevant memory task. Participants witnessed a video of a mock crime, made an identification or rejected the line-up, and rated their confidence. Critically, some participants slept between witnessing the crime and making a line-up decision, while others remained awake. The prediction that participants in the sleep condition would have greater discriminability compared to participants in the wake condition was not supported. There were also no differences in reliability.

Eyewitness Descriptions and Identifications of Familiar Perpetrators

This chapter discusses the role of an eyewitness, the importance of eyewitness testimony, and the different identification decisions that an eyewitness can make when the police have apprehended the guilty suspect or an innocent suspect of the crime in question. The chapter then discusses eyewitness recall of strangers, highlighting recent research focusing on an eyewitnesses’ ability to recall details about a perpetrator who is familiar to them. Furthermore, this chapter provides a description of other situations within the legal system in which familiarity recall may be required (e.g., the recall of familiar and unfamiliar events). The chapter also discusses familiarity in relation to how it may impact eyewitness identification accuracy by describing recent research that has utilized an eyewitness paradigm.

Is ROC analysis a tool that should replace probative analysis in studying lineups?

Purpose – The purpose of this paper is to explain why ROC analysis is an inappropriate replacement for probative analysis in lineup research. Design/methodology/approach – Taking as the medical example comparing two methods to detect the presence of a malignant tumor (Mickes et al., 2012), and operationally defining ROC analysis: radiologists are shown the results from two methods. Their confidence judgments create a graph of correct identifications by mistaken ones. The author can compare the methods on radiologists’ ability to differentiate sick from healthy. Lineup researchers create two distinct lineups. In target-present lineups, witnesses differentiate between the target and the foils, not the target and the innocent suspect. In target-absent lineups, witnesses cannot even differentiate between innocent suspects and foils, having seen none. Findings – Eyewitness ROC curves are similar to probative analysis, but provide less useful information. Research limitations/implications – Researchers ware warned against using ROC when conducting lineup research. Originality/value – Preventing inappropriate use of ROC analysis.

Polygraphic Examinations in Japan: Application of the Guilty Knowledge Test in Forensic Investigations

There are two main types of psychophysiological detection of deception in Held practice: the guilty knowledge test (GKT) and the control question test (CQT). A survey carried out for members of the American Psychological Association and the Society for Psychophysiological Research proved that many of the members consider that the GKT is superior to the CQT in its validity. Moreover, several experimental studies reported that the GKT produces fewer false positive errors (classifying an innocent suspect as guilty) than the CQT. In spite of these issues, the GKT is used less in North America and there are several researchers who insist that it is inapplicable in real-life criminal investigations. In Japan, however, the GKT has been extensively and successfully used in criminal investigations since the 1950s. Moreover, basic studies of the GKT, such as visual presentations of evidence, an automated diagnostic method by a computer and detecting guilty knowledge by using event-related brain potentials, are actively carried out in many Japanese laboratories to improve the method's reliability. In an effort to encourage the application of the GKT as an effective and scientific method in criminal investigations, this paper describes the status of the GKT in Japan.