French gendarmes' ability to make inferences while listening to witnesses: Implicit and interfering information curbs their comprehension

Forty French gendarmes from the Gendarmerie Nationale, and 40 laypersons completed two experiments to assess how they make inferences from testimonies. The first experiment targeted how inferences are made when the critical information on which a judgment has to be made is explicitly stated in the testimony or it is implicit and has to be inferred. The second experiment assessed the comprehension of statements when critical information about an event described by a witness was directly and clearly available in the testimony or embedded within irrelevant information and personal thoughts of the witness. Results showed that gendarmes had fewer false alarms than laypersons when the statements were explicit but had as many false alarms as laypersons when information was implicit and had to be inferred. It was also found that gendarmes had fewer false alarms than laypersons when the critical information was not embedded within irrelevant information but had as many false alarms as laypersons when irrelevant information was present. This study shows that being a gendarme involves better understanding of testimonies, but only as long as testimonies do not contain redundant, interfering, and implicit information. Otherwise, this superiority is lost.