How To Lie Effectively, According To Science


Robin Andrews

Science & Policy Writer

It's complicated. Marish/Shutterstock

Lying is complicated. Much of it has clearly pushed us into the terrible, everything’s-on-fire state we’re in today, but as this stellar piece in National Geographic explains, deception is a large part of what makes us human – and it’s still fairly mysterious. Now, a new study has given us clues as to what makes someone better at it than others.

Spearheaded by the University of Würzberg, this Journal of Experimental Psychology study takes a closer look at how speaking different languages plays a role in lying. Their conclusion? That telling the truth in a foreign language is more difficult compared to using a native lingo – which helps conceal those that lie.


The authors’ study lays out the problems with pre-existing research right from the offset. “Research on trustworthiness indicates that non-native speakers are perceived as less trustworthy than native speakers,” it begins, quite melancholically.

They then add that it’s still not yet clear whether or not people lie less effectively in a non-native language. Less effective liars would be seen as less trustworthy, but at the same time, using a second language could make telling the truth more difficult.

The team had two hypotheses about lying in a foreign language. One possibility was that it takes more cognitive effort to lie as compared to telling the truth, so having to speak a different language makes lying even more difficult than usual.

The other option is that lying arouses emotions. Communicating in a foreign language is somewhat less emotional than speaking in your mother tongue (for those fluent in the language, but perhaps not multilingual people), which means that lying in it conceals such telltale emotions.


The former suggests it’s more difficult; the latter infers it’s easier. So which is it?

In order to find out, the team arranged a series of experiments in which people were asked both neutral and emotional questions in their mother tongue – German – and in a foreign language – English.

Cues were given to indicate whether they should try to deceive the interrogator or not with their responses. As they answered, their response time, skin conductance (analogous to perspiration levels), and heart rate were measured.

Unsurprisingly, the team found that it takes longer to convey a lie than the truth – a key sign that someone’s trying to deceive you. What was unexpected, however, was that the response times of those using the foreign language were similar regardless of whether they were telling the truth or not.


That effectively shields lies in a foreign language from detection. This wasn’t to do with the deceptive answers, though, but rather the fact that telling the truth in a foreign language takes longer.

That suggests that the cognitive load hypothesis – that lying is more difficult in a second language because there’s more to think about – is partly right, in that it still takes a while to tell fibs. However, the emotional distance involved in using a foreign language cancels out this effect. The cognitive load effect ends up making telling the truth a prolonged effort.

The study has flaws. It only involved 50 people, and just two languages. It is nevertheless an insight into why telling the truth in a foreign language is more difficult.

The team think it “could explain the perceived lower trustworthiness of foreign language speakers”, noting that increased awareness about this effect may help to reduce this bias – a particularly pertinent suggestion in the current nationalistic climate.


  • tag
  • cognition,

  • language,

  • Emotions,

  • second,

  • deception,

  • lying,

  • truth,

  • foreign,

  • easier,

  • harder