Fool me twice: how effective is debriefing in false memory studies?

Deception is often necessary in false memory studies, especially when the study aims to explore the effect of misinformation on memory. At the end of the study, participants are debriefed, but does this eliminate the influence of misinformation? In the current study, we followed up 630 participants six months after they participated in a study in which they were exposed to fabricated political news stories. We compared the memories of these "continuing participants" for both novel and previously seen news stories to the memories of 474 newly recruited participants. Relative to new recruits, continuing participants were less likely to report a false memory for a story that they had been previously exposed to, and they were also less likely to report a false memory for a novel fake news story. Continuing participants were more likely to report a memory for previously seen true events than novel true events. Both groups of participants reported enjoying the experience and feeling confident that they understood which stories were fabricated. Importantly, this study did not find any negative long-term effects of participating in our false memory experiment, and even exhibited some positive effects.