From Hypotheses to Questions: Investigative Decision-Making Impact on Suspect Interview Planning

This study examined how police officers’ investigative decision-making, particularly how their capacity to generate multiple hypotheses relates to the open-mindedness of their suspect interview planning. We also explored associations between interview planning, cognitive flexibility (CF), need for cognitive closure (NFC) and professional experience. We hypothesized that the number of hypotheses generated would be: (1) positively associated with more open-minded interview plans; (2) positively associated with CF; (3) negatively associated with NFC. 107 Brazilian civil police officers (M_age = 41.62; 63.8% male) participated during a professional training course on investigative interviewing. Each participant planned a suspect interview for a fictitious missing-person scenario. Plans included investigative hypotheses, interview objectives, first question, interview topics, and detailed questions. Responses were coded using structured frameworks developed in prior research. Generating more investigative hypotheses was associated with more balanced and open-minded interview plans, including broader interview topics and more questions addressing alternative explanations. Professional experience showed a negative association with broader planning. CF and NFC were not significantly related to the number of hypotheses generated. Findings suggest that investigative open-mindedness is linked to more balanced, information-gathering investigative interview plans, while cognitive factors did not significantly influence interview planning. However, given the correlational design, no causal inferences can be drawn, and future experiments should address this.