Most of us like to think that we have moral standards, and there may be a psychological reason why.

A study published (paywall) today (May 16) in the Proceedings of the National Academy of Sciences indicates that when we act unethically, we’re more likely to remember these actions less clearly. Researchers from Northwestern University and Harvard University coined the term “unethical amnesia” to describe this phenomenon, which they believe stems from the fact that memories of ourselves acting in ways we shouldn’t are uncomfortable.

“Unethical amnesia is driven by the desire to lower one’s distress that comes from acting unethically and to maintain a positive self-image as a moral individual,” the authors write in the paper.

To investigate, Maryam Kouchaki, a behavioral research specialist at the Kellogg School of Management at Northwestern University and her colleague Francesca Gino at Harvard Business School conducted nine separate studies with over 2,100 participants. Over the course of their work, they found that people remember the times they acted ethically, like playing a game fairly, more clearly than the times they probably cheated.

“We speculated…that people are limiting the retrieval of memories that threaten their moral self-concept and that is the reason we see pervasive ordinary unethical behaviors,” Kouchaki wrote in an email.

Intuitively, these results make sense. We don’t like to think of ourselves as immoral people, and may come up with justifications (pawall) for our behavior that would indicate the contrary. The authors write that these results could indicate why certain acts of dishonesty are so pervasive, like hitching free rides on public transportation, stealing from the workplace, and even cheating on taxes.

Of course, not all of our indiscretions are easy to forget, particularly when there are lasting ramifications to our actions. “Strong consequences might reduce unethical amnesia with your rationale,” Kouchaki wrote. But simultaneously, she speculated, the emotional pain caused by remembering severely negative consequences could work as even more motivation to forget that we acted immorally in the first place.