Practice during investigative interview training is crucial for interviewers to develop the ability to adhere consistently to best-practice interview procedures. Given the constraints around using trained actors in the role of the child during practice interviews, this study examined whether officers themselves were able to play this role in a manner known to facilitate interviewers' performance. At baseline, 24 police officers' ability to adhere to five rules that were developed to train actors how to play the role of the child were measured. They were then given simple instructions about each of the five rules, and their ability to adhere to these rules was measured a second time. The results showed that participants naturally adhered to two of the rules at baseline (providing broad disclosure initially and responding with no more than four pieces of information to open-ended questions). Their performance improved for one rule (introducing conversational tangents) after receiving the simple instructions; however, participants' performance showed less improvement for the other two rules (responding with a non-feasible response to complex questions and responding to specific questions with few words). Overall, the results supported the use of fellow interviewers in the role of the child during practice interviews.