We’re really good at forgetting all the bad things we’ve done

In the early 2000s, psychologists at the University of Massachusetts, Amherst, conducted a study on everyday dishonesty. They recruited a few hundred students, put the students into pairs, and told the pairs to have 10 minute conversations with each other.

Each encounter was recorded with a hidden camera. Afterward, the researchers showed the students the tapes and asked them to point out every lie they uttered. On average, it turned out, each student told nearly two lies in those 10 minutes. Some told up to 12.

Had they relied on their own recollections, many students might have insisted on their innocence. But the tape held them accountable. “When they were watching themselves on videotape, people found themselves lying much more than they thought they had," one of the researchers said at the time.

That was just a 10 minute conversation. What if we scoured our everyday lives for dishonest moments? We all like to believe that we’re upstanding human beings, but in truth, most of us are constantly failing this or that moral test. We tell people we never saw their texts; we steal from supply closets; we jump turnstiles; we take too many napkins from Chipotle.

To be fair, swiping napkins is a minor sin. And lying is sometimes the kind thing to do, especially if we're trying to spare someone’s feelings. See how that works? We preserve our egos, in part, by self-justifying. We make excuses, or convince ourselves that our transgressions were minor.

Maryam Kouchaki, an assistant professor of management at Northwestern, and Francesca Gino, a professor of business administration at Harvard, argue that something else helps us cope with our own moral slouchiness. According to their research, people seem to be really good at forgetting all the bad things they’ve done.

“Because people value morality … they are motivated to forget the details of their [unethical] actions so that they can keep thinking of themselves as honest individuals,” they write in their new paper, published this week in the Proceedings of the National Academy of Sciences.

Since Kouchaki and Gino are both business school professors, they also have a catchy name for this behavior: “unethical amnesia.”

To try to show that memories of our shameful deeds fade faster, the researchers conducted a series of experiments. In one scenario, they asked subjects to play a coin toss game to win money. Participants could lie about the outcome of the game. Two days later, they followed up with a memory test. The people who cheated on the game reported fuzzier recollections of the coin toss game compared to the people who were honest.

Now, it could be that people who tend to cheat just have worse memories in general. But the researchers found that both the cheaters and non-cheaters in this experiment were equally likely to say that they remembered the details of what they ate for dinner two days prior. The cheaters didn’t seem to have an impaired memory overall; they seemed to be selectively forgetting the situation in which they behaved unethically.

Still, a weakness of this first experiment is that the researchers couldn’t control who cheated and who didn’t. So in a follow-up experiment conducted online, the researchers tried randomly making it impossible to cheat. They assigned people to play one of two versions of a betting game. One version of the game was set up to make cheating easy — the subjects could change their bets after the event and no one would know. The other version of the game did not give people the opportunity to cheat — subjects had to report their bets before the event happened.

Two days later, people who played the game that allowed cheating reported fuzzier memories of the game than people who played the strictly honest version of the game. These results suggest, again, that it’s something about the act of cheating that makes people forgetful, not that habitual cheaters tend to be more forgetful. When it’s impossible to cheat during a game, people tend to remember it better.

Immediately after the game, the researchers also asked the subjects about their self-image. Did people think of themselves as moral and trustworthy? Did they feel ashamed of themselves? Two days later, the people who were more ashamed were more likely to say that they couldn’t clearly remember the event. “The more dissonance they experience after cheating, the fuzzier the memory of their unethical actions become,” the researchers say in the study.

What’s going on here? Unfortunately, the study can’t tell us if people’s memories actually faded, or if people were suppressing the memories, or even if they were lying to the experimenters. That’s because the main tool the researchers used to measure people’s memories was a survey. People were asked to report how clear their memories felt, and how confident they were in their memories. This kind of subjective exercise doesn’t give us much insight into what is actually happening in people’s brains. Does shame interfere with memory formation? Does shame interfere with memory retrieval?

Further experiments using brain scanning or drugs that affect people’s memories might untangle some of those questions. For now, we have an interesting observation that squares with a lot of our own intuitions. The instinct to preserve our dignity and our sense of self-worth is surprisingly strong.