How to tell if someone is lying

Wouldn’t it be grand if our x-ray vision enabled us to separate the liars from the trustworthy? Being able to tell whether the used car salesman is really selling this car cheap or whether the shop assistant did inadvertently add that extra item on your bill. Or at work, being able to trust a colleague who seems charming enough but may just be screwing whatever they can out of you?

Lying is a deceptively complex concept. As we all create our own realities on the fly, the idea that my reality is not the same as yours is built into the system. We can disagree about what just happened and be entirely consistent with our own internal radar. This lends itself to gradations of truth.

The idea of a white lie plays on the need to protect someone from something. We lie in their best interests. Following this logic, the lies that we worry about are those that are designed to favour someone else over us.

Perhaps this opaqueness is why ‘thou shalt not lie’ did not make the top 10 commandments.

Lying is not a natural act. The sociopaths amongst us may be better at it, but it remains a challenge even for the most self-deceptive. Firstly, you must rearrange the facts to fit with the evidence. This is not always easy hence the saying that a liar will get caught in their own web.

Secondly, there is an element of guilt. We’re social creatures who like to roll with the herd. Our emotional response to breaking with the rules is to feel bad. Like all emotions, guilt is likely to motivate the liar to behave in certain ways to be consistent with the way they feel. Perhaps they will compensate for their actions, by acting in some other altruistic way.

So how can you tell if someone is lying? Here are some techniques from the professionals.

1) Pose a credibility question – this was a favourite tactic of a friend who was a stock analyst. He would start interviews with pretty straight-forward questions to build trust and relax his quarry. Then as he began to ratchet up the complexity of the questions, he would slip one in where he knew the answer – and that the interviewee would be expected to know too. A wrong answer here is a strong tell that things are not as they seem.

2) Deny, deflect, delay – we don’t like lying as a rule. It requires effort even for those that have limited emotional empathy, as they need to construct an alternate reality that still fits with the evidence. For this reason, the preferred first course of action is to try to not answer the question. So a politician may suggest that this question needs to be considered by some committee process, or they may suggest that is something that they could not have knowledge of. If someone is being evasive with their responses, the chances are that they are avoiding the truth.

3) Body language – while our words may say one thing, our movements can often say another. We often unconsciously register if someone’s body language is out of sync with their words. In fact, it’s been said that over 90% of communication is non-verbal. People who are lying will often try to create distance between themselves and the question – physically pushing back to create extra space. They may also close themselves – folding arms, legs or turning to one side – rather than meeting your gaze or opening their posture. This is not an exact science – some of us are nervous around people at the best of times. So it is relative, which is why detectives will try to gather a baseline behavior before applying the polygraph test.