Photo: Peter Glass/Getty Images

On a recent, truly excellent episode of the podcast Heavyweight, host Jonathan Goldstein attempted to solve a mysterious memory belonging to his friend Rob (Corddry, a comedian). Rob believed that, as a child, he broke his arm at camp. Rob’s family — his mother, father, sister, and brother — have no recollection of such an injury. At all. In fact, they vehemently deny it, insisting that the only Corddry sibling to suffer a broken arm was Rob’s older brother. Rob is certain, but so is his family. So who’s right? I won’t spoil it for you (it’s really a must-listen), but facts aside, there is another big question at hand: can a person come to believe their own often-repeated mythology, even when it’s patently untrue?

According to a study published in the journal of Applied Cognitive Psychology last week, the answer is a resounding, discomfiting yes. In an experiment, the study’s author, Danielle Polage, an associate professor of psychology at Central Washington University, provided her college student subjects with a list of events they may have experienced in childhood, asking them to rate them on their certainty that those events did (or did not) happen. Then, pretending not to know which of those items were untrue, Polage asked the subjects to read a scripted biography made up of half true and half untrue events, but to act as though all the events were true. The subjects were told that the experiment was meant to test their ability to lie, and were thus directed to add feasible color and detail to the false events to create a fuller story.

After they finished lying to her, Polage asked the students to again rate their certainty that each of these events had or had not happened. Fascinatingly (and a little creepily), subjects showed a statistically significant change in their beliefs, indicating that they became less sure that untrue events hadn’t happened to them after saying that they had. Conversely, when subjects were later asked to deny events that had happened to them, they became less sure that those events did take place.

Previous research has shown that false memories can be implanted, which is creepy enough, but for some reason I find it more troubling that humans can so easily convince ourselves we lived through something we never did.