The Impact of Interview Style on the Development and Maintenance of Rapport While Testing a Novel Measure for Rapport

Investigative interviews are a central part of policing. Rapport has been
shown to enhance information provision during investigative interviews. The impact of interview style or repeated encounters with law enforcement on rapport and information provision have rarely been tested in suspect interviews. This is a critical knowledge gap, as it is common practice for suspects to be interviewed more than once. It is therefore important to know how previous interactions with the police could affect future interactions in terms of rapport and information elicitation. Another major gap is that there is no gold standard measure of rapport. Previous research shows rapport being best observed via nonverbal behaviour, more precise: mimicry. We therefore measure rapport via nonverbal mimicry during investigative interviews using motion capture suits. Within two studies, we studied 1) If rapport differs depending on interview style and whether established rapport carries over to a second time point; 2) How different interview styles affect rapport, and; 3) If mimicry can serve as an objectively behavioural measure of rapport. Findings suggested that rapport maintains over multiple interviews and can recover where rapport was low
after the initial interview. An interview style focusing on the Information-gathering approach potentially increases rapport compared to an Accusatory-interrogation method, but only to a modest degree. This may have important implications for practice, because it suggests that good interviewing practice can lead to long term benefits in terms of cooperation with the police. Mimicry was not found to be a reliable measure of rapport.