Reckon you could sniff out a Traitor? (Picture: BBC/Studio Lambert/Llara Plaza)

Can you tell when someone is lying to you? 

If hit BBC show The Traitors is anything to go by, it may be harder than you think. 

In the show, people are split into two groups – the Traitors, and the Faithfuls. 

To win the prize money, the Faithfuls must work together to sift out the Traitors. Sounds simple enough, right?

Not quite. 

A study, published in the journal Cognition, found that when judging a group of people, we combine all their features into one ‘composite face’, and judge that face for a rough idea of whether the group is trustworthy or not.

This is known as an ‘ensemble perception’. 

Season 2 of the show has proven just as addictive as the first (Picture: BBC/Studio Lambert)

‘We know that we subconsciously judge whether an individual is trustworthy based on facial characteristics,’ said lead author Fiammetta Marini, from the University of Aberdeen.

‘For example, high eyebrows that seem surprised-looking in their shape, along with a U-shaped mouth, are usually perceived as trustworthy. Eyes close together or lower eyebrows are often perceived as untrustworthy.

‘These judgments are neither accurate nor reliable. 

‘Regardless, we make these split-second judgments and they have a big impact on our everyday lives, even if these impressions are not always accurate, they invariably shape our social behaviour.’

The researchers found we make this decision in around a quarter of a second. 

Although this social hack is a massive time saver as we can quickly gain social information, it can lead to some disastrous results – as seen on TV, with five traitors going into tonight’s final. 

‘It is important to remember that we are only talking about facial features,’ saidMaybe what it really shows is that we should focus on what people do, as opposed to judgments about whether we like the look of them,’ said Ms Marini, a PhD student.

‘This can explain why people may say things like “there’s just something about them I don’t trust” or “I don’t trust any of them” – and yes, it may explain why the Traitors are proving so elusive.’

The latest series of The Traitors comes to a conclusion on BBC One today.

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The Traitors have everyone up in arms.