Demonstrating detail in investigative interviews: an examination of the DeMo technique

Attaining an uninterrupted free report is at the heart of best practice investigative interviewing guidance. However, witnesses/victims do not naturally provide detailed accounts. Techniques have been developed to counter-act this, such as a Report Everything (RE) instruction. This research examined the relative effectiveness of an addition to the RE component, a demonstration of the level of detail, using a behavioural exemplar, by describing an innocuous object; the DeMo technique. Participants (N = 61) watched a mock crime video and asked to recall it using one of three instructions: (i) basic free report as the control, (ii) RE instruction, and (iii) RE instruction plus DeMo technique. Participants who were given the DeMo technique recalled more details than both the control and RE groups. Accuracy rates were similarly high across all conditions. The implications of using the DeMo technique within an investigative interview are discussed.