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

In three studies 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 false 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 experiment, condition 3 was changed to an audio condition in which visual cues were inaccessible. Results showed no differences between instruction conditions with regards to overall accuracy. Thus, we found no evidence that the simple instruction not to focus on nonverbal cues while judging veracity is an effective strategy to improve lie detection.