I’ve posted before about how cognitive dissonance (a psychological theory that got its start right here in Minnesota) causes people to dig in their heels and hold on to their beliefs even when faced with overwhelming evidence to the contrary.

Indeed, when people’s self-confidence is rattled (when facts intrude?), they may become even more hell-bent on sticking to their beliefs.

Now that we’re nearing the end of a truly nutty election cycle in which facts often have been ignored, forgotten and even reconstructed, I thought I’d revisit the topic.

In a recent post on his award-winning blog, Not Exactly Rocket Science, Ed Yong describes a new study by two Northwestern University marketing researchers, David Gal and Derek Rucker. “The duo carried out three experiments involving issues such as animal testing, dietary preferences, and loyalty towards Macs over PCs,” Yong writes. “In each one, they subtly manipulated their subject’s confidence and found the same thing: when faced with doubt, people shout even louder.”

Here’s Yong’s description of one of the ingeniously designed experiments [reader alert: British spellings]:

Gal and Rucker asked 88 students to write about their views on animal testing for consumer goods, but only half of them were allowed to use their preferred hand. This may seem random, but previous studies have shown that people have less confidence in what they write with the hand they’re less comfortable with. Indeed, that’s what Gal and Rucker found in their study. When asked later, the volunteers who didn’t use their dominant hand were less confident in their views.

However, they were also more likely to try and persuade others of those same views. When they were asked to write something to persuade someone else about their opinions, those who felt less confident wrote significantly longer missives. With a sliver of doubt in their minds, they spent more effort in their attempts at persuasion.

Gal and Rucker also found that this extra effort vanished if the volunteers had a chance to affirm their own identity beforehand. If they were asked to identify their favourite items (books, cities, songs and so on) before writing about animal testing, the choice of hand had no effect on their advocacy attempts. If they were asked to say what their parents’ favourite things were, the hand effect reappeared.

The results from the researchers’ other two experiments (involving the participants’ beliefs about vegetarianism/meat eating and Macs/PCs) were similar.

“In all three cases, Gal and Zucker found that doubt turns people into stronger advocates,” writes Yong. “More subtly, their study shows that this effect is stronger if someone’s identity is threatened, if the belief is important to them, and if they think that others will listen. It all fits with a pattern of behaviour where people evangelise to strengthen their own faltering beliefs.”

As Gal and Zuker write in their study, which appears in the journal Psychological Science:

“The present research also offers a warning to anyone on the receiving end of an advocacy attempt. Although it is natural to assume that a persistent and enthusiastic advocate of a belief is brimming with confidence, the advocacy might in fact signal that the individual is boiling over with doubt.”

Something to think about as you listen to all the angry politicians and political pundits this weekend.