Editor's note: The following essay is reprinted with permission from The Conversation, an online publication covering the latest research.

Most people believe that they are moral and good. They also believe cheating on a partner is wrong. So how do cheaters live with themselves after their infidelity? Understanding how they reconcile their indiscretions with their beliefs about themselves can help us figure out why “good people” cheat.

Dissonance theory predicts that when individuals’ thoughts and behaviors are inconsistent, something has to give. Have you ever wondered why anyone would be a smoker these days, given what we know about the link between “cancer sticks” and cancer? A smoker knows that smoking causes cancer, but might rationalize it by saying “I don’t smoke very much” or “My grandma smoked two packs a day and lived to be 90 years old!” By coming up with these rationalizations, people are able to preserve the impression that their behaviors and attitudes are consistent.

Similarly, cheaters might minimize the significance of their infidelity as a way to cope with knowing they did something wrong. The authors of a new study published in the Journal of Social and Personal Relationships propose that cheaters feel bad about their indiscretions, but try to feel better by reframing their past infidelities as uncharacteristic or out-of-the-ordinary behavior.

The experiment

To test this idea, the researchers randomly assigned people to be either “faithful” or “unfaithful” in four different lab experiments. Now, you are probably wondering how you make someone cheat on their partner (or not) in a psychology study. Even if researchers could create such groups in the lab, you may think that they probably should not do it anyway (you know, for ethical reasons). The researchers got around these problems by ingeniously banking on the fact that when you are in a relationship, you might still interact with other people you find attractive, and the degree to which you interact with attractive others could count as a mild form of infidelity.

Participants were instructed to think about a past romantic relationship and then to think about someone, other than their past partner, whom they were attracted to while they were in that relationship. For example, if Ted from “How I Met Your Mother” was a participant in this study, he would have been asked to think back on his (now terminated) relationship with Victoria, and reflect on how much he thought about Robin, interacted with her, and flirted with her while he was with Victoria by answering questions on an “infidelity scale”.

Here is the really clever part: Participants were given “false feedback” (or inaccurate information) to make them think that they were higher or lower than average regarding past infidelity compared to other participants. So, if Ted was assigned to the “unfaithful” condition in this study, he would have been made to believe that his past interactions with Robin were especially frequent and intimate – essentially, that he was relatively unfaithful to Victoria compared to other people who completed the infidelity scale.

The results showed that participants who were made to feel unfaithful had more negative emotions than those in the “faithful” condition. Those made to feel unfaithful were also more likely to report that they did not like themselves. In short, they experienced discomfort about their infidelity. They also tended to downplay their infidelity, reporting that it was not important and did not represent them (“It’s not who I typically am”).

In short, people know that infidelity is wrong, but some still do it. And when they do, they usually feel pretty bad about it. But through various forms of cognitive gymnastics, cheaters are able to discount their past indiscretions to feel better about themselves. Since the negative consequences, at least in terms of how they feel about themselves, are diminished, maybe they do not learn from their mistakes – and might be susceptible to cheating again in the future.

Benjamin Le does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations. This article was originally published at The Conversation. Read the original article.