The Field-Simulation Paradigm: Examining Witness Performance in Lab vs. Real-World Field Conditions.
Our Field Simulation Experiments
Since 2012 we have collected data on nearly 3000 participants using our field-simulation paradigm. The field-simulation paradigm was designed to combine the control of lab studies with the ecological validity of field experiments by enabling researchers to examine how eyewitnesses perform under highly realistic conditions, while still maintaining a high level of experimental control over the witnessing conditions and the presence of the culprit. This is accomplished by staging a mock crime and immersing participants in what they are led to believe is an actual police investigation, in which their identification would presumably lead to the arrest and prosecution of the suspect. Like field experiments, the police are the experimenters and it is assumed that the witnesses’ identifications will lead to the arrest of the suspect. However, unlike field experiments, ground truth of guilt is always known, so researchers can directly examine false identifications of innocent suspects, rather than being limited to examining mistaken filler choices. Additionally, because ground truth is known, investigators can also examine false identifications in showups conducted under field conditions, which could not be accomplished in field-experiments because showups have no innocent fillers. Moreover, since, culprit-presence is controlled and manipulated by the experimenters, this ensures equal numbers of innocent and guilty suspects are present across the conditions being tested. This level of experimental control enables researchers to make causal claims about which procedures result in better trade-offs between guilty-culprit and innocent-suspect identifications. This also allows investigators to examine base rate performance for accuracy and false identifications when using different procedures.
Field-simulations also have a major advantage over tradition field experiments, because, like lab studies, this paradigm permits experimental control over witnessing conditions. Because the researchers control all elements of the protocol from the staged crime to the identification procedures, they can manipulate exposure to the culprit. This allows investigators to systematically examine how certain estimator variables interact with the procedures being used.
Do witnesses perform the same way in the field versus the lab: Not necessarily.
This work has consistently found that when participants were led to believe their identifications were being made as part of an actual police investigation, witnesses at showups lowered their criterion for choosing, and were overconfident in their identification decisions.
Our most recent field-simulation studies compared showups to lineups under field compared to lab conditions. Results showed that the field-conditions had a very different effect on witness performance when using showups compared to lineups. For showups, field-conditions led witnesses to lower their criterion for choosing regardless of culprit presence. Notably, this difference was even greater when only examining the true-believers, who expressed no significant doubts about the reality of the field-simulation. However, the field-conditions appeared to have the opposite effect on lineup decision-making; resulting in decreased choosing regardless of culprit presence, which led to a commensurate decrease in both false-identifications and accurate culprit-identifications.
New Research Administering Lineups on Tablets in the field
Funded by the Arnold Foundation
Showups are primarily used when law enforcement personnel locate a suspect near the scene of the crime, but lack probable cause for arrest. Because law enforcement personnel can only detain the suspect for a short period of time, traditional methods of lineup construction are not practical. Thus, showups are justified in this exigent circumstance in which lineups are not feasible. In light of modern technology, it is more possible now than ever that law enforcement personnel could construct a lineup in the field in a matter of minutes and administer the lineup with an iPad. Yet, it is not a foregone conclusion that a photo-array lineup carried out with an iPad will outperform the live presentation of a suspect in a showup procedure. Indeed, it might simply be the case that the benefit of live presentation in a showup procedure outweighs the benefit of fillers in lineup procedures. In the present research, we compare six-person iPad-based lineups with showups in a simulated-field procedure in which law enforcement personnel administer identification procedures to eyewitnesses who believe they are involved in an actual criminal case. We recently collected data on over 1,000 participants using this method.
I Remember the Tattoo: Misidentifying an Innocent Suspect Can Alter a Witness’s Memory for the Perpetrator’s Face
Can mistakenly identifying an innocent suspect change your memory for the culprit’s face? Case studies of people who were falsely identified, convicted, and then later exonerated with exculpatory evidence have revealed that when witnesses become convinced of the suspect’s guilt, their memory for the culprit is often altered, such that when they remembered the crime, they recalled the face of the innocent suspect as the perpetrator. Although anecdotal cases studies of this phenomenon are relatively common, no extant controlled experiments have clearly demonstrated this effect. Findings from the current study demonstrated that misidentifying an innocent suspect resulted in a specific alteration to many witnesses’ memory for the perpetrator, and that post-identification feedback enhanced this effect. Participants viewed a video of a simulated and were led to misidentify an innocent suspect from a suggestive culprit-absent photo-array in which the suspect was the only viable choice. The innocent suspect either had a tattoo photoshopped onto his face, or, like the culprit, had no visible facial markings or tattoos. After making a selection, half the participants received post-identification feedback confirming their mistaken identification. Finally, participant-witnesses were asked to describe the perpetrator in their own words. Results revealed that 44.6% of participant-witnesses who misidentified the tattooed suspect mistakenly recalled that the carjacker had a tattoo on his face. As predicted, receiving confirming feedback significantly boosted erroneous reports of recalling the tattoo.
We conducted this experiment live, and also online. We found that the effect was more powerful live compared to MTurk. Indeed, we have made this comparison in other studies and found that the face-to-face interaction appears to enhance suggestive influence from the lineup administrator.
What happens when a witness either does not choose or selects a filler from the lineup and the officer prompts them to continue their search?
“Does Anyone Else Look Familiar?”: The Effects of Subtle Disconfirming Feedback on Confidence Judgments and Lineup Decisions
This study was designed to examine the effect of subtle disconfirming feedback on witness confidence judgments and lineup decision-making. Subtle disconfirming feedback took two forms in this study. Participants’ lineup decisions were either questioned by asking them in a neutral tone if they were sure about their choice and if anyone else looked familiar, or this same questioning was done in concert with skeptical gestures (e.g., shaking one’s head from side-to-side and squinting). It was hypothesized that subtle disconfirming feedback would lead to a decrease in witness confidence and the selection of additional photos, and that the effect would be strongest when the skeptical gestures were employed. In addition, we examined the relationship between confidence change following post-identification feedback and both memory for the perpetrator and suggestibility as measured by errors on misleading questions related to the event. Results revealed that subtle disconfirming feedback led to a significant decrease in confidence. Also, when participants were asked if anyone else looked familiar, more than 40% selected an additional picture; and of that group, the second choice was made with equal or greater confidence than their original decision 30% of the time. Moreover, suggestibility as measured by errors on misleading question was related to confidence change.
NEW RESEARCH ON JUROR DECISION MAKING: HOW GANG EVIDENCE AFFECTS JURORTS DECISION MAKING
In this series of studies we examined how the introduction of bias by depicting the defendant as a gang member can affect jurors memory for the evidence and their decision-making. In four different studies over 1000 participants viewed three different abbreviated simulated trials where biased was systematically varied, as the defendant was either described as being gang affiliated or not. Consistently jurors voted guilty more often when the gang bias was induced. Also, after deliberating in groups, many jurors continued to voted guilty in gang bias conditions even when reasonable doubt was clearly established, as evidence by no guilty verdicts in the no bias condition.
CA AB 333: OPUR RESEARCH CHANGING THE LAW
- This bill was based by on our research fdemonstrating how gang evidence biases juror decision making. This new law now requires bifurcation of gang-related evidence in prosecutions of crimes that are not clearly gang-related: An approach we proposed in the papers. Essentially, the law blocks the introduction of harmful character evidence at trail of previous associations with gangs if the crime is not directly related to gang activity.
Eisen, M. L. & Dodson, B, & Olaguez., A (2015). How Prejudicial is Gang Evidence? Washington College of Law, Criminal Law Practitioner.
Eisen, M. L. Dodson, B. & Dohi, G. (2014). Probative or Prejudicial: Can Gang Evidence Trump Reasonable Doubt? UCLA Law Review, Discourse
What happens when one witness hears another say that the perpetrator had a distinctive tattoo, and only one guy in the lineup has that type of tattoo; but he is not the actual culprit?
The effects of plausibility and retention interval on eyewitness conformity
One hundred and seventy seven participants watched a video of a simulated carjacking. Right after the video witness statements were taken from each participant; as they were asked to describe what they just witnessed. All sessions involved five participants, consisting of two confederates and three subjects. The confederates’ each made three errors in their reports (6 in total). These errors included included three pieces of plausible and three pieces of implausible information about the culprit. These suggestions involved distinctive and forensically relevant features of the perpetrator; including the suggestion that the perpetrator had a tattoo on his neck. After a 5-minute, 50-minute, or 48-hour delay, free recall was obtained from each participant individually, and they were asked to pick the perpetrator from a target present or absent photo array. In each of these photo arrays a filler with a tattoo on his neck was included. Results revealed a main effect for plausibility, the plausible misinformation was more likely to be included in the participants memory reports at each retention interval. Also, participants also selected the filler with the tattoo on his neck 38% of the time at the 5 and 50-minute retention intervals, and 36% of the time at 48 hours.