Lefties May Be Biased Toward the Left-Hand Side of the Ballot

Democracy is more subliminal than you think.

National Journal

Say it's Election Day. Once inside the booth, a voter feels a pang of anxiety. He's ambivalent and decides to pick a candidate at random.

The voter is a lefty. And though he may not realize it, the hand he writes with has influenced the candidate he votes for — the one listed on the left side of the booth. When his friends ask him how he voted, he says he guessed. But a subliminal bias is at play.

In a recent experiment published in the journal Political Psychology, candidates listed on the left-hand side of the ballot enjoyed a 15 percent bump among lefties compared with right-handed voters. "Righties implicitly think right is good, lefties implicitly think left is good," says Daniel Casasanto, a coauthor of the study.

And for such an arbitrary sounding reason, a race can be won or lost.


What does it say about democracy if elections can be thrown by the subliminal quirks of the brain?

It wasn't a leap for Casasanto to hypothesize that left- or right-hand dominance would influence voting behavior. He's found a similar effect before in nonpolitical settings. In one such experiment, he showed participants pairs of alien drawings called Fribbles, and asked how intelligent, honest, attractive, and happy they were — strange questions when you consider that a Fribble looks like this. The lefties responded more kindly to the aliens on the left, the righties more kindly to those on the right.

"Our bodies are an ever-present part of the context in which we use our minds, and should therefore exert a pervasive influence on the representations we tend to form," Casananto writes. According to that theory, what's true for the aliens should be true of politicians.

And it was. In an experimental election of two hypothetical candidates, each diverging on issues and each randomly sorted into a left or right spot on the ballot, "everyone, even righties, had a bias to select the candidate on the left, but that tendency was stronger in lefties," Casasanto says.

Some of the many controversial 2000 presidential election ballot boxes and voting booths sit in storage on Nov. 6, 2001, in Palm Beach, Fla. How might have the world been different if Al Gore was listed first?  (Joe Raedle/Getty Images)

Let's back up a bit.

Casasanto's research attempts to answer the "why" to one of the more confounding phenomena in democracy: the primacy effect, which is the tendency of candidates listed first on the ballot to receive more votes than they would if they were listed later.

A forthcoming paper in the journal Public Opinion Quarterly is perhaps the largest study on the primacy effect to date, analyzing all statewide California elections between 1976 and 2006. California rotates candidate ballot order district by district. While that randomization is not of the same rigor that a lab study would employ, it's as good of a natural experiment as the researchers can analyze.

The analysis found when candidates were listed first (no matter the ballot type), "on average, across all contests, candidates received nearly half a percentage point of additional votes compared to when they were listed either in the average of all later positions."

Furthermore, "82 percent of all candidates performed better when listed first than when listed later."

"Simulations suggest 9 percent of the races could have been different due to the primacy effect if one particular name order had been used throughout the state instead of rotating," the study's conclusion reads.

Considering this data, and assuming what's true of voters in California is true across the country, it's not an overstatement to say the fate of America has been forever changed because of this effect. In 2000, in Florida, George W. Bush won by less than 1 percentage point. And every ballot in Florida listed Bush first.

"If Florida had done what California or Ohio do, by rotating name order, we have very strong evidence to suggest, that most likely, Al Gore would have been elected president," Jon Krosnick, a study coauthor (and jazz drummer) tells me. "That's a pretty powerful implication that as we head up to the 2014 and 2016 elections — that there's something broke about this system."


"It would be really unfortunate if somebody learned about this literature and said, 'Oh boy, voters are idiots.' "

So is hand dominance a strong enough factor to influence a presidential race? Could a targeted lefty get-out-the-vote campaign tip a voting precinct one way or the other?

Let's break down the results of the Political Psychology paper. Righties showed a bias for the candidate on the left because it is the first name they read. That's consistent with other research on primacy, that there's a bias for the first in a list. Lefties showed that effect, as well as an additional left-hand bias: Lefties chose the candidate on the left because his was the first name they read and because they have a positive association with things on the left. Whereas among righties, the candidate on the left showed a 21 percent advantage, among lefties, that jumped up to a 36 percent advantage.

There's a huge caveat here. These results were pulled from an experiment on a fictitious election. And they are the first of their kind — it takes years of repetitive results to nail down a phenomenon. So take caution in extrapolation. "I don't expect that we would see anything like that enormous, ridiculous, percentage point difference in real elections," Casasanto says of the 21 percent and 36 percent advantages. "But in light of Jon [Krosnick]'s previous data. I think we have every reason to believe that these effects are and can be found in real elections."

Aside from the influence of hand dominance, Casasanto and his colleagues (Krosnick was also a coauthor on the Political Psychology paper) found the primacy effect was most prominent among people provided with the least information about the candidates, those who were most ambivalent about the candidates, those who had lower levels of education, and those least engaged in thinking about the election. Curiously, there's a stronger primacy effect for top-ticket candidates, such as for president or governor, than for down-ticket candidates. Krosnick theorizes this is true because people feel more of an obligation to vote in these contests, even when they don't have a clear opinion.

But as complicated as parsing down why people behave like this is, the solution to mitigate the bias is supremely simple: randomize the ballot order district-by-district, like California does, and present the names vertically to discount the left-hand bias. Though some states do rotate ballot order, Casasanto and his colleagues find most do not have such safeguards.


The question lurking in the background here is this: What does it say about democracy if elections can be thrown by the subliminal quirks of the brain?

Ballot order isn't the only psychological factor at play. Consider that children can predict election outcomes just by choosing among candidate headshots. That's how powerful our biases toward certain, competent-looking faces are. Facebook might have influenced thousands of young people to go to the polls in 2012 because the site told users which of their friends voted, increasing the social pressure to do the same.

"It would be really unfortunate if somebody learned about this literature and said, 'Oh boy, voters are idiots,' " Krosnick says. After all, it's just at most a few percent of voters who are showing these effects. But at the same time, our elections have to recognize that humans aren't completely rational. And when races become so tight, these quirks cannot be discounted.