Maria Konnikova reviews research on how misinformation affects our judgment:
Even when we think we’ve properly corrected a false belief, the original exposure often continues to influence our memory and thoughts. In a series of studies, [psychologist Stephan] Lewandowsky and his colleagues at the University of Western Australia asked university students to read the report of a liquor robbery that had ostensibly taken place in Australia’s Northern Territory. Everyone read the same report, but in some cases racial information about the perpetrators was included and in others it wasn’t.
In one scenario, the students were led to believe that the suspects were Caucasian, and in another that they were Aboriginal. At the end of the report, the racial information either was or wasn’t retracted. Participants were then asked to take part in an unrelated computer task for half an hour. After that, they were asked a number of factual questions (“What sort of car was found abandoned?”) and inference questions (“Who do you think the attackers were?”). After the students answered all of the questions, they were given a scale to assess their racial attitudes toward Aboriginals.
Everyone’s memory worked correctly: the students could all recall the details of the crime and could report precisely what information was or wasn’t retracted. But the students who scored highest on racial prejudice continued to rely on the racial misinformation that identified the perpetrators as Aboriginals, even though they knew it had been corrected. They answered the factual questions accurately, stating that the information about race was false, and yet they still relied on race in their inference responses, saying that the attackers were likely Aboriginal or that the store owner likely had trouble understanding them because they were Aboriginal. This was, in other words, a laboratory case of the very dynamic that [political science professor Brendan] Nyhan identified: strongly held beliefs continued to influence judgment, despite correction attempts—even with a supposedly conscious awareness of what was happening.