Module 5

Weighing what you hear: lie detection, body language, NLP and what actually helps

Lawyers, judges and jurors have always wanted to know whether a person is telling the truth. Many believe that they can tell from manner: a shifty glance, a pause, a fidget, a flat voice. Popular books and courses promise to teach the skill, often under the banner of body language or neuro-linguistic programming (NLP), with claims such as that the direction of a person’s eye movements shows whether they are remembering or inventing. The research is clear, and it is not what most people expect. Across many studies, people (including police officers, judges and customs officers) judge truth and lies from demeanour at little better than chance, they are confident in their judgements anyway and the cues that they rely on, such as gaze aversion and fidgeting, do not reliably separate truth-tellers from liars. Reviews of NLP’s central claims have found little support for them. What does help is quite different: checking an account against documents and other evidence, noticing whether it holds together and is plausible, whether it contains the detail that comes from being there, whether the person was in a position to know and whether they have a reason to shape it, and, where there is something to test, asking questions in ways that bring out more information. This module explains the research, the myths and the methods, and the Account Evaluator in the labs turns the methods into a checklist. Nothing here is a lie detector, and the course says so plainly. All the people are invented.

General education on listening and interviewing, using invented people, firms and events. It states psychological research in broad terms and is not a substitute for specialist training, and it is not legal advice. Rules on interviewing, contact with witnesses and represented persons, recording and the interviewing of suspects and vulnerable people differ between countries and change: check the rules that apply to you and take advice.