16/10/2013 13:27 BST | Updated 16/12/2013 05:12 GMT

Five Ways to Spot a Liar

Many people think they can spot a liar but research shows that most of us are only as good as chance when it comes to detecting whoppers. In my book Would I Lie To You, co-written by Dr Paul Seager, we explore the common mistakes ordinary folk make when it comes to identifying if someone is trying to pool the wool over your eyes. For example, many people think that blink rate or gaze aversion (being unable to look you in the eye) are reliable indicators of deception detection - but in most cases, they are wrong.

Here then are five more dependable ways to spot a liar; these are the cues that are the hardest for a liar to fake (for example, most liars know that gaze avoidance is thought of as a good cue to deception, so make great efforts to keep eye contact when they lie):

1. Inability to tell a story in a non-linear way; this means that they can tell their fake tale from beginning to end, but struggle more if asked to tell it out of sync. Trap them, then, by asking them about bits of the story in a different order and see if they struggle to answer you.

2. Lack of the word 'I'; in false accounts, people tend to drop the possessive and try to distance themselves from their account. The I may become we. For example, 'I went to the pub with some lads - I didn't even speak to a girl!' might indicate more truth than 'we went to the pub - it was just a lads night out'.

3. Use of passive rather than active voice: for example 'Tennis is one of Jane's favourite hobbies' (passive) rather than 'Jane loves playing tennis' (active). Passive tone can indicate that the liar is trying to distance themselves from their shifty tale (as might avoidance of the 'I' word above).

4. Increased repetition of common words and phrases: liars have enough to concentrate on with remembering their lies, so they tend to resort to tried and tested phrases to reduce their 'cognitive load.' Thus, you might find that with increased questioning, they tell their story in exactly the same way; truth tellers are often more able to use variety in their verbal expressions.

5. Mismatch of words with body language: liars might say one thing but their body language or facial expression contradicts them. For example, saying 'yes, I love your new hairstyle' but with folded arms, slight shake of the head, toneless voice etc.

Of course, if it were really this easy, we wouldn't have written a whole book on lie detection, but the above five are a good starting point for any wannabe lie detector. And, if you are the one trying to tell a whopper, now you know what to do.....

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