Once a Liar—Always a Liar?
Max Planck researcher Isabel Thielmann finds that dishonest behavior is consistent
Let us be honest—we have all been dishonest before. Even though no one likes to admit it, it is part of being human to tell the occasional lie or bend the truth. Yet personality research shows that some people are more prone to lying than others. So is it possible to predict who is going to lie and who is not? A new study by Isabel Thielmann, Research Group Leader at the Max Planck Institute for the Study of Crime, Security and Law, and three fellow researchers has found that previous dishonest behavior can be a predictor of future dishonest behavior. This finding contradicts earlier research that had assumed a high degree of variance.
The study examined how people behave when they are repeatedly put into a situation in which lying gives them an advantage without incriminating them—in which lying is worth it, so to speak.
The result: Someone who has lied once is likely to lie again in similar situations. The researchers also found an association between (dis)honest behavior and certain personality traits. What that means in practice? Previous behavior largely predicts future behavior, true to the saying, “Once a liar, always a liar.”
Earlier research on this topic had established little consistency in dishonest behavior, thus challenging theories that attribute dishonest behavior to certain personality traits. Isabel Thielmann and her co-authors come to a different conclusion: “Previous research looked into dishonest behavior across very different situations and drew the conclusion that it mainly hinges on the specific scenario. What we did was to measure dishonest behavior in three structurally similar situations to come to a less distorted assessment of consistency,” Thielmann explains. According to her, it makes most sense to examine how consistent a certain behavior is when the structure of an experiment is equally consistent.
Three experiments to establish consistency
What specific steps did the researchers take? They created three scenarios that were similar in one key aspect: In each instance, subjects were able to earn a bonus payment by giving a certain response, knowing that experimenters would not be able to trace whether their response actually represented the truth. That said, researchers were able to estimate the relation between someone’s tendency to lie and their self-reported personality traits.
What did they learn? In all three situations, significantly more people claimed a win than was to be expected if everyone had been honest. Even more importantly: “Being dishonest in one situation makes it likely that someone will also act dishonestly in other, similar situations”, Thielmann sums up. She sees this as counter-evidence to the prevailing assumption that lying varies notably depending on the situation.
Honest and humble people lie less frequently
In addition, the researchers were able to identify yet another association, i.e., that persons with certain personality traits—such as honesty-humility—are far less likely to lie repeatedly. In psychology, honesty-humility is one of six traits of the well-established HEXACO model of personality. Persons with a low score are considered to be unfair, corruptible, and stingy, and to show little regard for societal conventions.
These findings make it easier to predict future behavior than previously assumed. However, Thielmann emphasizes: “You always have to be careful to what extent you can actually generalize from one situation to another. While previous behavior is a good source of information, other factors also play a crucial role when it comes to anticipating future behavior; there is no such thing as a perfect prediction.”
The study was recently published in the renowned Journal of Personality and Social Psychology.