There May Be a More Reliable Way to Detect a Liar

In the age-old game of predicting deception, there’s a brand-new approach.

Posted Feb 24, 2018

Antonio Guillem/Shutterstock
Source: Antonio Guillem/Shutterstock

Figuring out who will be truthful is as important a determination to make as any you might make in your life. Your quest to identify what's a lie ranges from distilling the newsfeed you receive on a moment-to-moment basis to trying to decide if a salesperson is giving you a truly good deal for a truly good product. Psychology addresses the question of dishonesty from a range of perspectives, such as interpreting body language or counting the number of “uh’s” in a person’s speech. However, it would also make sense that personality would figure into the equation. Putting this idea to the test, University of Cape Town (South Africa) psychologist Yolandi-Eloise Jansevan van Rensburg and colleagues (2018) explored academic dishonesty in a context easily investigated with college undergraduates. Although their focus is on this specific type of cheating, the results of this study also have implications for understanding dishonestly on a larger scale.

Van Rensburg and her colleagues note that a large percentage (43%) of college students admit to having cheated at some point and in some way on exams. This estimate comes from a range of studies conducted between 2002 and 2013, with nearly 135,000 participants. In a way, although cheating on campus is a headache primarily for instructors, the problem also takes on significance when you consider that some of those cheaters are now serving the public, sometimes in situations involving life or death decisions. Who wants a cheater conducting brain surgery or doing your taxes?

The personality traits that the South African researchers believed would be most related to academic deception stem from the so-called “HEXACO” model that includes as one if its components the honesty-humility dimension. As you can most likely guess from the term, scores on this personality attribute are related to what the researchers call “counter-academic behavior.” In other words, people with low scores on the honesty end of the continuum should be more likely to commit “multiple ethical transgressions within an academic context” that would include cheating and plagiarizing among other behaviors such as abusing substances and holding low personal standards. Whether honesty-humility scores would include cheating specifically within this range of counter-academic behavior became the study’s empirical question.

According to van Rensburg et al., it is necessary to break the honesty-humility scores down further in the effort to predict cheating. Honesty refers to being fair and trustworthy, and unwilling to engage in behaviors designed to provide personal gain such as exploiting, stealing, lying, and of course, cheating.  People high in humility avoid being greedy and regard themselves as not particularly entitled to special treatment. Putting the two together, people may want to get ahead and hope to get special treatment (i.e. be low in humility), but honesty puts the brakes on their doing so, acting as a “control element” against engaging in counterproductive behavior.

Using an online sample of 308 South African students ranging from 18 to 47 years of age, with an average age of 23, van Rensburg and her collaborators assessed cheating both with direct questions about counter-academic behavior as well as with a disguised measure of cheating in the form of an online task that participants were to score themselves. The online cheating task was administered prior to the personality test to ensure that participants wouldn’t guess the actual purpose of the study and then be influenced by the honesty questions when they performed the task.

The online cheating measure was cleverly designed to tempt participants to cheat by giving them the opportunity to win money if they performed well. Participants were told they should not use any unauthorized help such as using a calculator, nor to change their answers once they started seeing the correct scores. After completing the task, participants then reported on whether or not they had cheated in the process of scoring themselves or using any of that unauthorized help. To assess counter-academic behavior, the researchers asked participants a series of questions regarding such examples as submitting a class paper or project that was not their own work (misrepresentation) and turning in work that was of poor quality and lower than their true potential or ability (low personal standards).

Think now about what you would do in the online task scenario. Would you try to change your answers or give yourself an honest grade based on which ones you got right and which you got wrong? If you believe you would refrain from cheating, why would this be? Would you feel it was unfair to receive unearned money or would you just feel that you were being insincere? Think too about whether you’d really want money you hadn’t earned. Is it worth it to get an extra few dollars in terms of your own self-respect and integrity, or would you stop at nothing to try to game the system?

As it turned out, the fairness dimension ranked above all else in predicting who self-reports engaging in counter-academic behavior. With fairness including an adherence to social norms and unwillingness to take advantage of others, the authors reasoned, people with high scores on this trait should stay away from all forms of behaving badly in academic settings. For the online cheating test, though, it was greed avoidance that provided the strongest predictive value. That material gain, small though it was, provided sufficient incentive for the greedy students to grab what they could.

Breaking honesty-humility down into its components, then, and differentiating between general college misbehavior and cheating on a specific task allowed the South African team to pinpoint the distinct personality traits that lead people to lie to get what they feel they deserve. If you generalize beyond an academic situation, the findings suggest that the people most likely to cheat their way to the top are, at their core, greedy. Their desire to acquire material goods allows them to suspend their own sense of right and wrong. Those individuals who uphold the values of fairness will, by contrast, avoid the more general range of unsavory behaviors that include ethical transgressions. 

If you want to figure out who to trust, the van Rensburg et al. study suggests you do a quick assessment of fairness and greed avoidance. Even if you dangle attractive goodies to the people high in greed avoidance, they’ll be able to resist temptation. You can conduct your own experiments of giving them the opportunity to earn something they don’t deserve and see how they behave. The people who believe in fairness, similarly, can be put to the test by finding out if they would try to get away with bending the rules if they could. Of course, you can also see if they do. If a salesperson fails to charge them for an item, do they point this out, or furtively leave the scene as fast as possible?

Finding fulfillment in your own personal search for success means not cheating to get what you want. Learning to figure out who to trust in your relationships means looking not so much at their nonverbal communication but at the more easily observable, and perhaps reliable, conduct.


van Rensburg, Y. J., de Kock, F. S., & Derous, E. (2018). Narrow facets of honesty-humility predict collegiate cheating. Personality and Individual Differences, 123199-204. doi:10.1016/j.paid.2017.11.006