Police officers' and students' beliefs about telling and detecting trivial and serious lies

This questionnaire study investigated whether 52 police officers and 54 students expect differences between trivial (low stake) and serious (high stake) lies which are told by themselves or by others. We investigated differences in how often such lies occur, how difficult it is to detect them, whether telling these lies results in nervousness and requires mental effort and whether verbal and nonverbal behaviours would give these lies away. Results revealed that police officers and students had similar ideas about these issues, although these were not always accurate. For example, both groups reported that serious lies require more mental effort and are more stressful for the liar than trivial lies, but neither of the two groups indicated that this would affect liars' behaviour accordingly.