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What Do You Think Makes Someone a Liar?

New research shows why liars take what they think is the easy road to deception.

Lying is such a common feature of human behavior that you may occasionally expect deception even from those who are closest to you. Has your partner ever “rounded down” the cost of a new pair of shoes or falsely claimed that someone else in the family spilled the vinegar in the cabinet?

Did you ever catch a co-worker taking home an extra ream of paper? What about the people you don’t know who lie and cheat? Over the course of the 24-hour news cycle, how many times have you heard journalists report the many instances in which a politician’s words failed the fact check test?

When you stop and think about it, what do you believe makes people liars in these situations? Is it a streak of psychopathy? Is your partner just trying to avoid your getting mad over a budget-busting expense? Or does your paper-snitching coworker typically try to get away with snitching office supplies?

Next, ask yourself whether these liars and cheaters know they’re being dishonest or if they believe their behavior is justified? According to a new study by University of Michigan’s Julia Lee and colleagues (2019), the key to understanding why people lie is to explore an individual’s so-called “lay” theory about honesty.

People will engage in deceitful and dishonest behavior if they believe that behaving ethically is just too much effort. After the fact, they will make “self-serving justifications” (p. 660) to rationalize their unethical behavior. Adding to this is the question of whether it's even possible to get away with a fib. They figure if other people aren’t going to call them out, then it’s an “other person problem,” not their own.

Think of situations in your life when you were tempted to cheat. Perhaps you didn’t feel like getting up early for work, and you figured your boss wasn’t going to be in that day anyway. You got up when you felt like it instead of struggling to haul yourself out of bed when the 6 a.m. alarm went off. It took less effort to be late than to be on time.

However, if you were going to be totally honest with yourself, it would mean seeing yourself in an unflattering light. It’s easier to blame your boss for being a sloppy supervisor than to blame yourself for being a cheat.

Such behavior, according to Lee et al., is a function of being tempted by the situation but also by your "moral identity." A truly upright individual will be honest no matter what. You can count on such a person to behave according to the honor system. This is someone who won’t sneak a peek at an answer to a trivia game question or try to hop on a bus without paying for the ride.

Across three studies, Lee and her fellow authors tested their predictions about their “effortful” theory of dishonesty by seeing whether those who thought telling the truth was too much work would, in fact, behave deceitfully when given the chance. People who believe, in contrast, in the lay theory that honesty doesn’t take effort would “lack available justifications for their honesty and may behave honestly as a result” (p. 660).

Furthermore, a person’s lay theories about honesty should play a stronger role in determining whether the person would behave honestly, according to the study's predictions, when there’s no temptation present or when they feel that they’re likely to get caught.

In the first study, participants took a test of their “implicit” or unconscious attitudes toward honesty by completing an online test that measured whether they saw it as more effortful to be honest or dishonest. Following this, they were assigned the task of finding as many 4-letter words as they could from a letter matrix (like the game “Boggle”), with the rules being that they couldn’t reuse a letter in the matrix in the same word, all letters must be adjacent, and no proper names were allowed.

The cheating here was easy to detect. Participants wrote down their words, reported how many they had come up with, and submitted this to the experimenter. A surprising 30% entered at least one illegitimate word, with some of them coming up with nine fake words in one trial. As the authors expected, people who unconsciously associated lying with lack of effort were more likely to have cheated in reporting their scores.

In the second study, undergraduate participants from both the U.S. and Southeast Asia participated in a lying-effortful manipulation. One group read an article arguing that lying is more work than telling the truth with, for example, the claim that: “It is easy to be an ethical person. People often find that figuring out the right thing to do involves making simple decisions.”

In the honesty-as-effortful condition, the participants read an article claiming that “It is difficult to be an ethical person. People often find out that figuring out the right thing to do involves making hard choices” (p. 663). Next, participants completed an experiment in which they were offered the choice of lying to earn $2.00 versus telling the truth to earn $.50. Again, the finding supported the prediction that seeing honesty as effortful (via the article's claims) would lead participants to be more likely to lie.

Finally, the third experiment employed a similar frame, but added a component that led participants to think that they could get away with dishonest behavior. These participants answered a series of math questions presented to them by a computer program that timed their responses. In the “weak” situation, participants were told that, after seeing a problem, they had five seconds to provide their answer before it appeared on the screen before them. As soon as they knew the answer, they were supposed to press the space bar.

However, they were led to believe that the program would not record their pressing the space bar, meaning they could just sit and wait for the right answer to appear. Thus, if they were looking for justification for their dishonesty, they could blame a faulty program. In the weak (no temptation condition), participants were told that only after they pressed the space bar would they see the answer. As in the previous study, participants read articles to present one or the other effortful theories of honesty. The outcome measure was whether they took advantage of the weak situation’s temptations.

In this final experiment, cheating did in fact occur as a combination of a person’s theory of honesty as effortful combined with the strength of the situation to force honest responding. Cheating was more likely in the weak situation when participants read the honesty-as-effortful passage.

The authors unfortunately didn’t consistently measure individual difference variables across all three studies to identify who is particularly likely to fall prey to temptation. However, in the first study, they did include a measure of moral identity. For people high in this quality, the lay theory of honesty was less likely to determine their tendency to cheat at the word game. It would have been interesting to find out more about this possibility. Even without this individual difference factor, however, it seems likely that situations can provide strong influences on how honestly or dishonestly people behave.

To sum up, there’s no simple feature that distinguishes the honest from the dishonest. However, believing your fulfillment comes from doing the right thing can perhaps lead you to make tough but honest choices in important life decisions.

Facebook image: Daniel M Ernst/Shutterstock


Lee, J. J., Ong, M., Parmar, B., & Amit, E. (2019). Lay theories of effortful honesty: Does the honesty–effort association justify making a dishonest decision? Journal of Applied Psychology, 104(5), 659–677. doi:10.1037/apl0000364