Of the 206 participants, 173 fingered the "thief" with varying degrees of certainty. But the person who had picked up the laptop -- the "real thief" -- wasn't even in the lineup.
That 173 people thought they had picked the real culprit is pretty startling, but the researchers called the following result "astonishing."
When the participants were told that someone had confessed to committing the "crime," a whopping 61 percent changed their identification, "in each and every case identifying the confessor" as the perpetrator.
The researchers contend that the false confession left the entire process "contaminated," because it "corrupted the evidence itself," namely the testimony of witnesses.
In the second study, by psychologists Jason Chan of Iowa State University, Ayanna Thomas of Tufts University and John Bulevich of Rhode Island College, participants both young and old produced a counterintuitive finding. It would seem that sitting down with someone else and recalling an incident immediately after it happened would cement that memory, making it less likely to be altered by subsequent information.
That turned out not to be the case in this study. In separate experiments 84 undergraduate students and 60 older adults (average age 72.5) revealed a "surprising pattern," as the researchers put it. They showed "dramatically heightened susceptibility to misinformation" later if they had been interrogated immediately after the event.
"Our results provide a first look into how immediate recall affects later eyewitness suggestibility," the researchers conclude. "Contrary to the expectation that immediate recall would enhance retention of details of a witnessed event and thus reduce an eyewitness's susceptibility to misinformation, we found that immediate recall actually intensifies the misinformation effect (for both younger and older adults)."
It's not certain why that should be the case, but the researchers suggest several possibilities. It may be, for example, that subsequent information -- even if false -- causes the witness to re-examine that first interrogation and tweak the details.
"These results confirm the notion that recall not only indicates what one knows, but also changes what one knows, and sometimes these changes can have far-reaching, and perhaps negative, consequences," the researchers conclude.
As a high level federal official noted in a press conference a couple of years ago, there are things we know, and things we don't know, and things we know we don't know, and things we don't know we don't know.
And on too many days, what we don't know sends the wrong person to prison.