In a way, lying is one of the most human acts. It draws on our unique cognitive abilities, from planning ahead to mentally simulating other people’s perspectives. Because lying is such a complex process, psychology researchers have long been interested in liars and why they lie.

One way researchers have approached the topic of lying is by investigating what kinds of people tend to lie most often. The latest example comes in the form of a study from scientists in Poland.

The study looked at how two different kinds of traits influence people’s likelihood of lying: personality traits and cognitive ability.

Intuitively, both these kinds of traits have the ability to affect someone’s tendency to lie. Personality might influence someone’s overall level of honesty and their willingness to be less than forthcoming with the truth while cognitive ability might influence whether someone is able to actually get away with lying. But it’s unclear how these two types of traits interact.

To learn more, the researchers created a series of tasks in which people had to choose how honest they would be. The researchers then surveyed these people to learn about their personality.

It turned out that some personality traits predicted how much people would lie in simple ways. For example, people who were less agreeable – that is, less friendly, trusting and inclined to get along with others – were prone to lying more.

However, some personality traits only predicted how deceptive people were when cognitive ability was also taken into account. In particular, extraversion by itself wasn’t associated with lying, but extraversion in combination with intelligence was. To put it another way, extraverts didn’t tend to be bigger liars, but intelligent extraverts did.

According to the authors, this suggests that some personality traits correlate with lying only when cognitive ability is also taken into account. That is, a liar has to be both willing and able – personality is part of the “willing,” but intelligence might be an important part of the “able.”

Another takeaway of this study is, well, you know what the science says about smart extraverts: you can’t trust ‘em. Of course, you also can’t trust broad generalizations from correlational data, so you might want to take that into account too before cutting all intelligent extraverts out of your life!

Image: Flickr/The Open University under CC-BY-NC-ND 2.0