Facilitating Falsification: Devil’s Advocacy in Dutch Police Investigations

To mitigate the risk of this bias, police investigators should devote effort to exploring and attempting to falsify alternative hypotheses about a crime. In the Netherlands, investigators in complex capital crime investigations are instructed to apply devil’s advocacy (DA) to increase discussion and testing of alternative investigative theories.

This study provides a first quantitative examination of whether DA influences reasoning about evidence in crime investigations. Police investigators who regularly work with DA (n = 63), investigators who do not (n = 76), and laypersons (n = 88) read a fictional investigation report and judged the likelihood that the prime suspect was guilty both before and after asking follow-up questions and receiving additional information.