No evidence that instructions to ignore nonverbal cues improve deception detection accuracy

Research has consistently shown people predominantly rely on undiagnostic nonverbal cues when detecting deceit, whereas verbal cues are more accurate. In three experiments, we investigated whether the simple instruction not to focus on nonverbal cues would make people focus more on diagnostic verbal cues and hence more accurate in detecting lies. Participants judged the veracity of true and deceptive statements and either received (1) no instruction, (2) the instruction to ignore nonverbal cues, or (3) to ignore nonverbal cues and focus on verbal cues instead. In the second and third experiments, condition 3 was changed to an audio condition in which visual cues were inaccessible. Results showed no effect of instruction on lie detection performance. Overall, we found no evidence that the simple instruction not to focus on nonverbal cues while judging veracity is an effective strategy to make people focus more on verbal cues or to improve lie detection.