Ground Rules in Forensic Interviews: Should We Make Practice More Applied?

Introducing ground rules is recommended in many forensic interview best-practice protocols, but children do not always use them when they should. There is not yet a consensus in the literature on the best way to teach the rules, and many of the practice methods researched are not feasible for practitioners. Additionally, increased intensity of practice can lead to adverse effects on other aspects of child testimony too. We draw on cognitive learning literature to understand how to better facilitate ground rule use amongst children in forensic interviews. Ninety-three children between the ages of 5-12 from Greater Wellington region, New Zealand, participated in a staged event at their school and were interviewed using the National Institute of Child Health and Human Development (NICHD) Protocol (Lamb et al., 2018) 2-3 weeks later. At the interview, children practised the ground rules ‘I don’t know’ (IDK), ‘I don’t understand’ (IDU) and ‘Correct me’ (CM) in one of four ways which varied by the degree of match between the practice and interview context. Children were asked difficult questions designed to elicit the rules throughout the interview, and coding children’s accuracy of reporting also examined the broader effects of practice method and rule use. No significant effects were found between the practice method and responses to difficult questions for the IDK and CM rules. The Control condition, which received no ground rules instruction or practice, was significantly different to the other practice conditions for the IDU rule. In addition to this, there was no significant effect of practice method or competency at using ground rules on children’s general accuracy about the event. Several possible explanations for this pattern of results are explored in the discussion section.