According to psychologist Professor Richard Wiseman, the key to detecting lies is to listen rather than watch. In a mass participation experiment for the BBC, viewers struggled to identify lies when watching video, but performed better when only hearing audio or reading a transcript.
Wiseman's experiment featured former Question Time presenter Robin Day, who was filmed twice discussing his favourite movie – once truthfully and once with lies. The clips were shown on Tomorrow's World, while the soundtrack aired on BBC Radio and the transcript appeared in the Daily Telegraph. Results showed that visual cues distract from verbal content, and skilled liars control body language more easily than their voice.
Liars tend to drop personal pronouns like 'me', 'my' and 'I', possibly to avoid incriminating themselves, and generally say less. Robin Day spoke about half as much when lying. Another telltale sign is a longer response latency – the pause between question and answer.
Wiseman's research also reveals that close friends and partners are more easily deceived. Those in long-term relationships are often overconfident in their ability to detect lies but are actually worse at it. 'The better you get to know someone, the easier it is for them to lie to you undetected,' he said.
