Psychologists suggest that a new phenomenon is emerging whereby sharing on social media may begin to blur the line between individual and collective memories. These effects may be particularly important in the context of Internet-based misinformation and fake news.

Communication shapes memory, and memories shape how people think about the future. Research on pairs of people conversing about the past shows that a speaker can reinforce aspects of an event by selectively repeating them. In other words, things that get mentioned get remembered — by both speaker and listener. There’s a less obvious corollary: related information that goes unmentioned is more likely to fade than unrelated material, an effect known as retrieval-induced forgetting.

These cognitive, individual-level phenomena have been proposed as a mechanism for memory convergence — the process by which two or more people come to agree on what happened. But recent research suggests that memory convergence is more likely to occur within social groups than between them — an important finding in light of survey data suggesting that 62% of US adults get their news from social media, where group membership is often obvious and reinforced.