Eyewitness identification procedures for multiple perpetrator crimes: a survey of police in Sweden,Belgium, and the Netherlands

ABSTRACT

A considerable proportion of crimes involve multiple perpetrators. Yet, little is known about how police officers construct, administer, and record eyewitness identification procedures for multiple suspects. An online survey of law enforcement agents in Sweden, Belgium, and the Netherlands (N?=?51) was conducted to obtain an initial understanding of police perceptions of prevalence and characteristics of multiple perpetrator crimes, and to examine identification procedure practices given the little to no guidance provided for police. Practice converged when it came to the use of sequential, photographic lineups, but diverged between and within countries on whether or not suspects of multiple perpetrator crimes should be placed in separate lineups. Results specifically highlight contextual cuing as one critical area for future research in identification for multiple perpetrator crimes (i.e. placing multiple suspects in the same lineup or asking eyewitnesses to look for a specific suspect).     

Commentary on “Studying Eyewitness Investigations in the Field”: A Look Forward

Schacter et al. (2007, this issue) address the controversy surrounding an Illinois pilot project that attempted to compare sequential versus simultaneous police lineup formats. The statement by these experts will guide the design and execution of future field lineup experiments. This commentary discusses three aspects of field studies that pose challenges as lineup experiments are interpreted: the imprecise meaning of the dependent measure (eyewitness decisions), the limitations of single studies, and the necessity to devise public policy from incomplete knowledge. A combination of laboratory and field information provides the means to determine best practices in eyewitness identification procedures.     

The effect of authority and social influence on eyewitness suggestibility and person recognition

This study investigated the influence of an authority figure on eyewitness identification. Participants watched a staged crime and then were administered a photo lineup by either an authority (policeman) or non-authority figure (civilian). Participants in the authority condition were more likely to choose a lineup member than those in the non-authority condition. There was no effect of authority, however, on the accuracy of the identification decisions. The lack of a deleterious effect suggests that the presence of a police officer during identification procedures does not create an unduly suggestive situation or have undesirable effects on eyewitness identification decisions. Although witnesses' choosing behaviors did not increase the rate of identification errors, the effect of the administrator's authority on choosing was reduced when unbiased instructions (vs. biased instructions) were presented to the witnesses. Thus, support was found for the use of neutral instructions during eyewitness identification procedures.     

Age differences (or lack thereof) in discriminability for lineups and showups

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 that contained the perpetrator or a designated innocent suspect. Receiver operating characteristic (ROC) analysis showed that identification accuracy was higher from a lineup than from a showup for both age groups, even if the lineup was biased. In addition, calibration curves revealed that witnesses were underconfident when choosing from a fair lineup but overconfident when choosing from a showup. These results reinforce prior research asserting the superiority of lineups over showups.     

Sequential lineup presentation promotes less-biased criterion setting but does not improve discriminability

When compared with simultaneous lineup presentation, sequential presentation has been shown to reduce false identifications to a greater extent than it reduces correct identifications. However, there has been much debate about whether this difference in identification performance represents improved discriminability or more conservative responding. In this research, data from 22 experiments that compared sequential and simultaneous lineups were analyzed using a compound signal-detection model, which is specifically designed to describe decision-making performance on tasks such as eyewitness identification tests. Sequential (cf. simultaneous) presentation did not influence discriminability, but produced a conservative shift in response bias that resulted in less-biased choosing for sequential than simultaneous lineups. These results inform understanding of the effects of lineup presentation mode on eyewitness identification decisions.     

Social Influence in Eyewitness Recall: A Meta-Analytic Review of Lineup Instruction Effects

Past research has considered the impact of biased police lineup instructions upon eyewitness lineup performance. Biased instructions either suggest to the eyewitness that the perpetrator is in the lineup or otherwise discourage a no choice response. A meta-analysis of 18 studies was employed to review the hypothesis that biased instructions lead to greater willingness to choose and less accurate lineup identifications than do unbiased instructions. The role of moderating variables in the instruction procedure was also considered. In support of the hypothesis, a significantly higher level of choosing followed biased instructions. Lineup type moderated performance accuracy, however. For target-absent lineups the increased level of choosing following biased instructions resulted in reduced identification accuracy. Biased instructions within a target-present lineup generated a higher level of confidence, but had minimal impact on accuracy. Implications for police practice are discussed.     

PC_Eyewitness and the Sequential Superiority Effect: Computer-Based Lineup Administration

Computer technology has become an increasingly important tool for conducting eyewitness identifications. In the area of lineup identifications, computerized administration offers several advantages for researchers and law enforcement. PC_Eyewitness is designed specifically to administer lineups. To assess this new lineup technology, two studies were conducted in order to replicate the results of previous studies comparing simultaneous and sequential lineups. One hundred twenty university students participated in each experiment. Experiment 1 used traditional paper-and-pencil lineup administration methods to compare simultaneous to sequential lineups. Experiment 2 used PC_Eyewitness to administer simultaneous and sequential lineups. The results of these studies were compared to the meta-analytic results reported by N. Steblay, J. Dysart, S. Fulero, and R. C. L. Lindsay (2001). No differences were found between paper-and-pencil and PC_Eyewitness lineup administration methods. The core findings of the N. Steblay et al. (2001) meta-analysis were replicated by both administration procedures. These results show that computerized lineup administration using PC_Eyewitness is an effective means for gathering eyewitness identification data.     

Prior knowledge influences interpretations of eyewitness confidence statements: ‘The witness picked the suspect,they must be 100% sure%

When an eyewitness identifies a suspect from a lineup, it is important to know how certain they are about the decision. Even though eyewitnesses are likely to express certainty with words, past research shows that verbal confidence statements (e.g. ‘I’m pretty sure’) are prone to systematic misinterpretation. Until now, no one has examined how an evaluator's prior knowledge, such as which lineup member is the police suspect, influences their interpretation of eyewitness confidence about a lineup identification. Experiments 1 and 3 show that participants perceived the identical statement of confidence as meaning a higher and lower level of certainty, respectively, when the eyewitness's selection either matched or mismatched the police's suspect. Experiment 2 shows that these effects generally persist when the bias manipulation is manipulated between-subjects. Finally, Experiment 3 finds that clarifying the witness's statement with numeric information (e.g. I’m 80% sure) does not eliminate the influence of biasing information.     

Field Experiments on Eyewitness Identification: Towards a Better Understanding of Pitfalls and Prospects

The Illinois pilot program on lineup procedures has helped sharpen the focus on the types of controls that are needed in eyewitness field experiments and the limits that exist for interpreting outcome measures (rates of suspect and filler identifications). A widely-known limitation of field experiments is that, unlike simulated crime experiments, the guilt or innocence of the suspects is not easily known independently of the behavior of the eyewitnesses. Less well appreciated is that the rate of identification of lineup fillers, although clearly errors, can be a misleading measure if the filler identification rate is used to assess which of two or more lineup procedures is the better procedure. Several examples are used to illustrate that there are clearly improper procedures that would yield fewer identifications of fillers than would their proper counterparts. For example, biased lineup structure (e.g., using poorly matched fillers) as well as suggestive lineup procedures (that can result from non-blind administration of lineups) would reduce filler identification errors compared to unbiased and non-suggestive procedures. Hence, under many circumstances filler identification rates can be misleading indicators of preferred methods. Comparisons of lineup procedures in future field experiments will not be easily accepted in the absence of double-blind administration methods in all conditions plus true random assignment to conditions.     

A Re-examination of the Effects of Biased Lineup Instructions in Eyewitness Identification

A meta-analytic review of research comparing biased and unbiased instructions in eyewitness identification experiments showed an asymmetry; specifically, that biased instructions led to a large and consistent decrease in accuracy in target-absent lineups, but produced inconsistent results for target-present lineups, with an average effect size near zero (Steblay, 1997). The results for target-present lineups are surprising, and are inconsistent with statistical decision theories (i.e., Green & Swets, 1966). A re-examination of the relevant studies and the meta-analysis of those studies shows clear evidence that correct identification rates do increase with biased lineup instructions, and that biased witnesses make correct identifications at a rate considerably above chance. Implications for theory, as well as police procedure and policy, are discussed.     

Eyewitness Identification in Actual Criminal Cases: An Archival Analysis

This study analyzed 271 actual police cases in order to address several prevalent issues in the eyewitness literature. Suspect identification (SI) rates were obtained for 289 photographic lineups, 258 field showups, 58 live lineups, and 66 lineup identifications preceded by earlier identifications. SI rates were assessed for 3 levels of extrinsic evidence: no extrinsic evidence, evidence of minimal probative value, and evidence of substantial probative value. The SI rates for the photographic lineups were assessed as a function of delay, same vs. cross-race conditions, witness type, and weapon presence. SI rates declined significantly over time; SI rates were significantly greater for the same-race condition. SI rates were much greater for field showups than photographic lineups, 76% vs. 48%. The SI rates for the field showups did not vary as a function of eyewitness conditions. The relation between confidence and suspect/foil identifications for the live lineups was significant and moderately high. The utility of archival identification studies for eyewitness testimony research is discussed.     

A Re-examination of the Effects of Biased Lineup Instructions in Eyewitness Identification

A meta-analytic review of research comparing biased and unbiased instructions in eyewitness identification experiments showed an asymmetry, specifically that biased instructions led to a large and consistent decrease in accuracy in target-absent lineups, but produced inconsistent results for target-present lineups, with an average effect size near zero (N. M. Steblay, 1997). The results for target-present lineups are surprising, and are inconsistent with statistical decision theories (i.e., D. M. Green & J. A. Swets, 1966). A re-examination of the relevant studies and the meta-analysis of those studies shows clear evidence that correct identification rates do increase with biased lineup instructions, and that biased witnesses make correct identifications at a rate considerably above chance. Implications for theory, as well as police procedure and policy, are discussed.     

Co‐witness information influences whether a witness is likely to choose from a lineup

Purpose. Much crime is witnessed by more than one eyewitness, and witnesses may learn information about other witness's decisions throughout the identification and trial process. The objective of this paper was to investigate whether hearing about a co‐witness's type of lineup decision and subsequent confidence level affects another witness's type of lineup choice. Methods. A total of 304 undergraduate students watched a crime video with a confederate co‐witness. After the video, the witnesses completed an identification task. Prior to completing the task, the participant learned that the confederate co‐witness either chose from or rejected the lineup and was subsequently confident or not confident in that decision (or heard no co‐witness information). Participants completed the identification task using either a target present (TP) or target absent (TA) lineup. Results. Overall, those who heard the co‐witness chose from the lineup were more likely to choose from the lineup than those who heard no co‐witness information or who heard the co‐witness rejected the lineup. In addition, witnesses who chose from the lineup and heard the co‐witness chose from or rejected the lineup expressed more confidence in that choice if the co‐witness was more confident versus if the co‐witness was less confident. Conclusions. In cases of multiple witnesses, identification decisions may not be independent pieces of evidence. Therefore, it is important that police separate co‐witnesses throughout the identification process.     

Realism and eyewitness identification research

The importance of realism in eyewitness identification research is examined as the basis for both the credibility and utility of the information it provides. Without knowledge of how laboratory eyewitnesses behave differently from real eyewitnesses, the relevance and external validity of identification studies may be questioned. Factors differentiating these identification contexts are discussed. Witnesses in identification studies are in social decision-making contexts similar to those of real eyewitnesses when their decision to choose someone or to reject the lineup may have a significant impact on others' lives. Two studies are reported which preserve aspects of realism. Both presented witnesses with a realistic vandalism. The second maintained realism through the identification situation. The first study demonstrated effects of biased instructions on witnesses' willingness to make a lineup choice and on identification errors (with the offender present and absent). The second study showed an unexpected preference of witnesses for making an identification when the supposed consequences for the suspect were to be severe. To evaluate the generalizability and utility of laboratory studies it is important to determine whether their results and related theoretical analyses survive the transposition to more realistic contexts. Realistic studies should serve as benchmarks against which simulations are compared and their generalizability evaluated.     

Opinions of attorneys and law enforcement personnel on the accuracy of eyewitnes identifications

A survey was conducted to obtain the opinions of attorneys and law enforcement personnel regarding several important aspects of eyewitness evidence: (1) legal procedures concerning eyewitness evidence; (2) estimated frequency of mistaken eyewitness identification; (3) the effects of certain witness/ suspect characteristics on identification accuracy; (4) the amount of emphasis placed on eyewitness evidence by judges and juries; (5) the relationship between a witness' identification accuracy and certainty; and (6) the effect of stress and arousal on identification accuracy. The questionnaire was sent to a sample of defense and prosecuting attorneys in each of Florida's 20 Judicial Circuits, to each of the 67 county Sheriff's Departments in Florida, and to 100 randomly sampled Police Departments in Florida. Prosecuting attorneys and law enforcement officers indicated that they regard eyewitness identification as relatively accurate and that judges and juries appropriately emphasize its importance. Defense attorneys, on the other hand, felt that eyewitness identifications are often inaccurate and are overemphasized by triers of fact. The implications of these findings for the criminal justice system and their possible applications within the legal system are discussed.     

Predictors of eyewitness identification decisions from video lineups in England: A field study

Eyewitness identification decisions from 1,039 real lineups in England were analysed. Identification procedures have undergone dramatic change in the United Kingdom over recent years. Video lineups are now standard procedure, in which each lineup member is seen sequentially. The whole lineup is seen twice before the witness can make a decision, and the witness can request additional viewings of the lineup. A key aim of this paper was to investigate the association between repeated viewing and eyewitness decisions. Repeated viewing was strongly associated with increased filler identification rates, suggesting that witnesses who requested additional viewings were more willing to guess. In addition, several other factors were associated with lineup outcomes, including the age difference between the suspect and the witness, the type of crime committed, and delay. Overall, the suspect identification rate was 39%, the filler identification rate was 26% and the lineup rejection rate was 35%. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

The Effects of Pre-admonition Suggestions on Eyewitnesses’ Choosing Rates and Retrospective Identification Judgments

Pre-admonition suggestion is an identification-relevant comment made to an eyewitness by a lineup administrator before the lineup admonition. Quinlivan et al. (2012) found that their suggestion inflated mistaken identification rates and retrospective identification. However, the suggestion used was a compound statement, making it unclear which component influenced choosing rates. The current experiment was conducted to parse out the effects. Participants (N = 211) viewed a crime video and received either one component of the compound suggestion (a suggestion to pick or that the witness had paid substantial attention), both components, or no suggestion. All participants received an admonition, made an identification choice, and answered questions about their witnessing experience. The results demonstrated that the pick suggestion increased mistaken identifications from a perpetrator-absent lineup whereas the effects of the attention suggestion were restricted to the retrospective judgments. These results show support for the role of secondary (non-memorial) processes in eyewitness identification.