Supporting Witness Recall and Increasing Witness Cooperation Using Self-Generated Cues and Social Influence

Abstract

The programme of research that follows addresses two key challenges faced by officers on the frontline of policing: (i) the elicitation of full, detailed, reliable accounts from witnesses, and (ii) increasing the cooperation of reluctant witnesses. The ultimate aim of the research that follows is to identify techniques which can be utilised systematically in the field to equip police officers with evidence-based, simple, and effective interview techniques appropriate for a given situation. In addressing the first of these challenges I draw on key principles of memory (spreading activation, encoding-retrieval specificity, and cue distinctiveness) and propose three distinct self-generated cue mnemonics (a keyword grid, event-line, and concept map). An empirical test of these mnemonics suggests that overall use of self-generated cue mnemonics can increase the amount of correct information reported in a free-recall statement without a cost to accuracy when compared to other-generated cues. As such, self-generated cue mnemonics are an effective and easily implemented means of facilitating witness recall. In addressing the second of these challenges I present the findings of a detailed survey of experienced investigating officers. This addressed (i) practitioner perceptions of both the frequency and common features of encounters with reluctant witnesses, and (ii) effective practice techniques for eliciting information or evidence and building rapport with cooperative and reluctant witnesses. Findings suggest that relationship-based techniques might be particularly effective with reluctant witnesses. On the basis of this I argue that social influence techniques represent a viable means of increasing cooperation and disclosure from reluctant witnesses. A systematic review of compliance literature was conducted with a particular focus on techniques that may increase compliance in an investigative context (i.e. a large request requiring ongoing compliance and with a cost far exceeding a potential benefit). The findings of this review suggest that sequential requests (foot-in-the-door and door-in-the-face requests) may be of practical value in obtaining information from reluctant witnesses. Following this a series of empirical studies assess the effectiveness of these techniques in increasing cooperation of reluctant witnesses in both online and face-to-face contexts. Overall these studies suggest that sequential requests can increase compliance with requests for information. Furthermore, the novel paradigms proposed in Studies 3 and 4 represent a considerable advance in enabling research on reluctant witnesses.