We’re rarely rational when we vote because we’re rarely rational, period

Photo credit: Kaitlin McKeown/Associated Press

By Robert M. Sapolsky

Science can tell us lots about how voters will make their decisions in 2016. To appreciate those findings, first free yourself of the idea that humans are rational beings.

Rationality has taken a hit in various domains of decision-making. Economics used to be thought of as a realm of pure rationality, something disproven, for starters, by the million-plus Pet Rocks sold around Christmas in 1975. Formal behavioral economics research comes to much the same conclusion more systematically. For example, people make radically different choices about an economic scenario depending on whether it is described in terms of risk or gain (“you have a 50% chance of losing X number of dollars,” versus “you have a 50% chance of gaining X”).

Human decision-making is subject to implicit influences in other realms as well. In one study involving thousands of cases of parole-board decisions, a highly significant predictor of whether an inmate was granted parole was how long it had been since the judge had eaten. Justice may be blind, but don’t expect to get a sympathetic hearing from someone whose stomach is gurgling.

Other research shows our sensitivity to all sorts of unconscious cues. People think potato chips taste better if they hear crunching sounds in the background as they eat, rate a beverage as tasting better if it’s served in more expensive-looking surroundings. Ask people their favorite detergent; if they’ve just read a paragraph containing the word “ocean,” they’re more likely to choose Tide — and then concoct some supposedly rational reason why it’s the very best.

Which brings us to how people go about voting for a political candidate. It’s a rare voter who carefully reads a candidate’s position papers on every conceivable topic. Instead, we typically vote based on a candidate’s stance on a subset of topics, assuming there will be a certain consistency on other topics. Or we follow party lines, or choose based on endorsements — if A agrees closely with B’s politics, and B is voting for C, A is on pretty safe ground voting for C even if C is a complete unknown.

Another conscious component of political decision-making is voting for experience or competence, rather than a platform. This is so common that one study found that candidates judged to look more competent had won elections 68% of the time (perhaps we don’t so much vote for competence as for the appearance of it). Competence at least seems like a pretty rational criterion — after all, who wouldn’t want competence in our leaders? — until you wind up voting for someone who competently implements things you oppose.

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