'Liars may be harder to spot than thought'

It may not be as easy to spot liars as thought, according to a study which has found that verbal and physical signs of lying are harder to detect than people believe.

Tests reveal that people are skilled at identifying commonly displayed cues -- such as hesitations and hand gestures -- but these signs are produced more often when someone is telling the truth.

Liars are also skilled at suppressing these signals to avoid detection, researchers found.

Psychologists used an interactive game to assess the types of speech and gestures speakers produce when lying, and which clues listeners interpret as evidence that a statement is false.

Jia Loy, from the University of Edinburgh in the UK, created a computerised two-player game in which 24 pairs of players hunted for treasure. Players were free to lie at will.

Researchers coded more than 1,100 utterances produced by speakers against 19 potential cues to lying -- such as pauses in speech, changes in speech rate, shifts in eye gaze and eyebrow movements.

The cues were analysed to see which ones listeners identified, and which cues were more likely to be produced when telling an untruth.

The team found listeners were efficient at identifying these common signs.

Listeners make judgements on whether something is true within a few hundred milliseconds of encountering a cue.

However, they found that the common cues associated with lying were more likely to be used if the speaker is telling the truth.

The study helps understand the psychological dynamics that shape deception, researchers said.

"The findings suggests that we have strong preconceptions about the behaviour associated with lying, which we act on almost instinctively when listening to others," said Martin Corley, of the University of Edinburgh.

"However, we don't necessarily produce these cues when we're lying, perhaps because we try to suppress them," Corley said.