Facts only the perpetrator could have known? A study of contamination in mock crime interrogations.

Abstract

This paper examines contamination in interrogations: the process by which an interrogator divulges privileged information to a suspect. Hypotheses: In Experiment 1, we predicted that mock investigators would communicate critical crime details when they interview mock suspects about a crime-and that innocent and guilty suspects alike would later produce confessions that contained these details. In Experiment 2, we hypothesized that observers who listened only to the confessions would exhibit a greater guilt bias than those who also had exposure to the eliciting interview. Method: Experiment 1 (N ϭ 59) used student participants in a mock crime scenario to test whether contamination is natural to communication even in the absence of external incentives. In Experiment 2, MTurk participants (N ϭ 499) listened to audio-clips from Experiment 1 to test whether presenting observers with the full interview decreases guilt ratings for false confessors. Results: Investigators divulged crime information to both innocent and guilty suspects, and even false confessions later included accurate details. Although Experiment 2 observers exhibited a guilt bias, exposure to the interview (not just the confession) attenuated this effect for innocent confessors. Conclusions: The information disclosure associated with contamination is a normal cognitive process that occurs even without external incentives to secure a confession. Experiment 2 showed that seeing contamination in action may decrease judgments of guilt for innocent suspects. Interrogations should be recorded in their entirety to provide fact finders with an objective record of the source of crime details contained within narrative confessions. Public Significance StatementThese results provide a preliminary understanding of how contamination occurs as part of a natural communicative process. Importantly, they suggest that lay observers can become sensitive to false confessions given the right information. This is a significant finding because contaminated false confessions often appear to indicate the suspect's guilt, even when the suspect is truly innocent.

Eyewitness identification in its social context.

“…Police officers also may communicate information to witnesses that could alter the accuracy of their identification decisions without altering the ability of witnesses to discriminate among guilty and innocent suspects or altering the conservativeness of their criterion for making an identification. Much like interrogators communicate details of the crime to innocent suspects during interrogations (Alceste et al, 2020), police officers could provide witnesses with details about a suspect’s characteristics while interviewing them about what they saw, especially if the officers have pre-existing expectations about who might be likely to have committed a particular crime in a particular neighborhood (i.e., they have “usual suspects”). Probably more common, given the number of jurisdictions that continue to use single-blind lineup procedures (Kovera & Evelo, 2017), is a situation in which a police officer, who knows which lineup member is the suspect, administers the identification procedure to a witness and consciously or unconsciously steers the witness toward identifying the suspect, irrespective of the suspect’s guilt (Kovera & Evelo, 2017, 2020).…”

Distinguishing True From False Confessions Using Physiological Patterns of Concealed Information Recognition – A Proof of Concept Study

“…While informed innocents could still be distinguished from guilty participants on a group level, individual classification on a case-to-case basis remains challenging. If no procedures are in place to prevent or observe the process of contamination in the interrogation room (see Alceste et al, 2020), such as recording police interrogations to document the original source of each detail appearing in the confession, innocents might be classified as knowledgeable in the CIT.…”

Intrinsic motivation in a virtual reality mock crime affects participants’ willingness to invest more effort in deceptive interviews

“…Due to ethical considerations, participants typically experience mock-crime activities that are non-violent such as a theft (e.g. 4 , 14 ) or burglary (e.g. 8 , 9 , 15 ).…”