[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

Confession of a crime is considered highly persuasive in court. It seems inherently honest. Why would an innocent confess guilt? It appears counterintuitive to basic human self-interest.

And yet, innocents do confess, and studies have shown that they are highly persuasive, even when jurors know they were coerced. According to the Innocence Project, false confessions contributed to 25% of wrongful convictions in the U.S. in 2008.

Perhaps more disturbing is that the confession itself can corrupt evidence that would otherwise excuse a defendant. This according to research published this month in the journal www3.interscience.wiley.com/journal/118505413/home.

Scientists had 206 subjects witness a "staged" crime and then were asked to pick the perpetrator from a line up. They were later told that their choice denied the crime, and nearly 30 percent changed their identified pick.

But the greatest change occurred when participants were told that another person, not the person they picked, had confessed to the crime. Now, 61 percent changed their identification, choosing the confessor.

When asked to explain their change, subjects revealed they were actually convinced by the confessor, and not simply complying with it, saying, "His face now looks more familiar than the one I chose before."

Despite the presumption in law that different types of evidence are to be considered independent, this research shows just how tough it is to keep human nature from seeping in and tainting hard logic.

—Christie Nicholson

60-Second Psych is a weekly podcast. Subscribe to this Podcast: RSS | iTunes

60-Second Psych is a weekly Podcast. Subscribe to this Podcast: RSS | iTunes