Politics, lies, and your brain

Following up on this earlier post on “source amnesia,” and the tendency for political (and other) mistruths to “stick”: I guess it’s no surprise the topic is getting attention as the current political season reaches ever-more-absurd levels of frenzy. Braulio sends this item from Very Short List:

Earlier this year, political scientists at Duke and Georgia State described the Bush administration’s claims about Iraqi WMDs to a group of adults, then gave those same people a convincing explanation that Iraq did not, in fact, have a WMD program in the works. How did the people react? Liberals became even more convinced that Iraq had no nuclear or chemical weapons; conservatives became even more certain that it did, with 64 percent of them insisting that Saddam was hiding the evidence.

Basically a classic instance of cognitive dissonance, no? (Subject comes up in Buying In, for whatever that’s worth.)

And today I see Freakonomics links to this Washington Post column on the same subject, mentioning the Duke experiment and others. In one, Yale political science prof John Bullock showed subjects the transcript of a NARAL ad that claimed John Roberts supported “violent fringe groups and a convicted clinic bomber.”

Bullock then showed volunteers a refutation of the ad by abortion-rights supporters. He also told the volunteers that the advocacy group had withdrawn the ad. Although 56 percent of Democrats had originally disapproved of Roberts before hearing the misinformation, 80 percent of Democrats disapproved of the Supreme Court nominee afterward. Upon hearing the refutation, Democratic disapproval of Roberts dropped only to 72 percent.

Republican disapproval of Roberts rose after hearing the misinformation but vanished upon hearing the correct information. The damaging charge, in other words, continued to have an effect even after it was debunked among precisely those people predisposed to buy the bad information in the first place.

The upshot of this and other experiments, The Post’s Shankar Vedantam writes, is that “refutations can strengthen misinformation.” And although I happen to have used an example showing this among Democrats, Vedantam says the tendency is “especially” true “among conservatives.”