An examination of layperson perceptions of the use of explicit and implicit social influence strategies in witness interviews

Fallon, Laura (2021) An examination of layperson perceptions of the use of explicit and implicit social influence strategies in witness interviews. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

The use of social influence in witness interviews, particularly implicit influence strategies, is an emerging practical and scholarly concern. In particular, how laypeople perceive such strategies is critically important, as they may one day serve as jury members tasked with evaluating witness evidence. Across four experiments, layperson perceptions of the use of explicit and implicit influence strategies in witness interviews were examined. In Experiment 1, participants (N = 293) read a witness interview transcript in which the interviewer employed an explicit influence strategy (i.e., threat), implicit strategy (i.e., minimization), or no strategy, and answered questions about the exchange between interviewer and interviewee. In Experiment 2, participants (N = 293) viewed an excerpt from a witness interview in which the interviewer used one of six influence strategies (i.e., threat, explicit leniency, four types of minimization) or no strategy, and rated the consequences the witness would face if they complied with the interviewer or failed to do so, and various aspects of the interviewer’s behaviour. In Experiment 3 and 4 (N’s = 286), participants read a transcript of a simulated murder trial where an explicit or implicit social influence tactic was used to convince an alibi witness to change his story (threat, explicit leniency, high-level minimization, low-level minimization, unprompted change, no-change). Participants were asked to render a verdict and answer questions about the alibi witness interview described in the transcript. The results from the first two experiments, in line with previous research, indicated that while laypeople can detect the message conveyed by implicit influence strategies, they do not fully recognize the potential risk of using such strategies. While Experiment 3 and 4 indicated that the use of explicit or implicit influence strategies did not impact verdicts – which is in line with findings in the suspect literature – there was also no impact of the alibi witness’ testimony on verdicts at all, suggesting that there are fundamental differences between witness admissions and confessions from suspects when it comes to their impact on courtroom decisions. Implications of these findings for the evaluation of witness statements in the courtroom are discussed.

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