Why Many Bernie Supporters Won't Defect To Hillary

People cast their vote at the Canterbury Town Hall polling station in Canterbury, New Hampshire, on February 9. New research shows that people vote to reinforce their own sense of identity rather than to support a candidate's policy positions. Shannon Stapleton/Reuters

People are more likely to vote in a way that reinforces their own sense of identity rather than to choose among competing policy proposals, say researchers at Duke University.

In an opinion piece published October 18 in the journal Trends in Cognitive Science, one of the paper's authors, Scott Huettel, a psychologist and neuroscientist, said that voting is a way to make a statement about who you are and what you stand for. An African-American might vote for Barack Obama to affirm "yes we can." Or a woman may endorse Hillary Clinton to make a statement about glass ceilings.

Voting can strengthen a person's identity as a mother, an environmentalist or an American, Huettel says. It also reflects how you want to be seen by others.

This does not mean that voters dismiss a candidate's policy positions. "We think of the balance between identity and policy as analogous to a dial," Huettel says. "When people think more about identity, like when considering an appeal to their social class or sense of self, then that diminishes the effect of policies upon their votes."

This notion of identity overriding policy preferences may explain why some Bernie Sanders supporters are reluctant to back Clinton, even after their candidate lost the Democratic primary. A poll published by The Economist/YouGov at the beginning of October showed that 45 percent of Sanders's supporters still refuse to "defect" to the Clinton camp.

"Many still hold out support because voting for her would seem like a betrayal of their personal identity," says Huettel. Plenty of Sanders's supporters proudly believe themselves to be more progressive and liberal than Clinton voters. "If policy were the core driver of support, then supporters of Sanders should all have readily jumped over to Clinton," he says.

Huettel and his co-author, Libby Jenke, came to their conclusions using mathematics to calculate the relative utilities a voter would get from various policy and identity variables.

Their work exemplifies the kind of insights that can come from weaving social and cognitive psychology into political science. This has become more common in the past 15 years or so, says Rachel Kranton, a Duke University economics professor who wasn't involved in the study. The applications extend beyond voting. We dress a certain way because it's a form of self-expression. We buy Mac laptops and drink Starbucks coffee because it projects a certain image.

"Throughout our lives, we make all sorts of decisions that are based on identity, and voting is no exception to that," says Kranton.

The new research is especially useful in predicting voter choice in primary elections, where differentiating candidates based on their policy positions can be tricky. They're all from the same party and are likely to hold similar views. Instead, voters look to other identity-related factors, such as religion, gender, race and social class, to find common ground with a candidate.

The recent Brexit vote in Great Britain is a stark example of voting that centered on identity. Roughly 40 percent of those who identified as "British" voted to leave the European Union. In contrast, this figure was much higher—70 percent—among those who identified as "English."

"For many people, the vote to leave the European Union is a signal that you supported your country, you're patriotic, you're a nationalist," says Huettel.

If Huettel is correct, voters heading to the ballot box are holding up a mirror to themselves. The vote they cast is a way of saying this is who I am. A Republican. A Democrat. A strong woman. A businessman.

That's how it usually works. But things might be different this Election Day, when both candidates have huge unfavorable ratings. Instead, many voters might be hoping that mirror cracks.