When Monkeys Are Better Shoppers Than Humans

Photograph by Tim Flach/Getty Images

A lot of psychology can be summed up thusly: People are suckers. The interesting question, though, is how it is we’re so easily influenced in some ways rather than others, and why. One example of this tendency is how we react to prices—in particular, how we internalize something’s price tag, and how it shapes our tastes.

Studies have found that people not only prefer more expensive products to less expensive ones, they actually enjoy them more. If you want someone to really relish a bottle of wine, simply tell them it cost $50. If you want them to like it less, tell them it cost $5. This isn’t just conspicuous consumption: The pleasure center in the brain actually lights up more when a person thinks they’re drinking a more expensive bottle of wine than a cheap one. In that particular study, everyone was drinking the same wine and being told different prices. In another study, participants who paid higher prices for sports drinks got a bigger energy boost out of them when asked to subsequently do a series of mental puzzles.

A team of Yale psychologists has a new paper out that looks at why that might be. Their approach is not to look at people, but monkeys, a small New World monkey called the capuchin. Capuchins can be taught to participate in rudimentary market transactions—they can learn to trade tokens for treats, and they can learn that certain treats have consistent prices.

The Yale team did a series of studies in which they showed that capuchin monkeys would learn to differentiate based on price. In one study the treats were different colored chips of flavored ice, in another different colored pieces of Jell-O; in others they were Kix or Crunch Berries cereals dispensed from cups with symbols that denoted their “brand.” In each study, the different types of treats were given different prices, and the monkeys picked up on that. They figured out they could get more for their money with one “brand” of treat than the other, and they would respond like bargain-conscious shoppers, spending their tokens on the cheaper treats rather than the premium ones.

Afterward, however, when they were given the chance to choose between the different treats without having to pay for them, the monkeys didn’t show a preference for the more expensive treats. They either went with their preexisting preferences or just chose at random.

The point of the study was not to show that monkeys are somehow more in touch with their preferences than humans—though anyone who has regretted paying more for a brand-name item when the generic would have worked just fine might feel a twinge of embarrassment. The point was to look at one explanation of where the human susceptibility to pricing might have emerged. One explanation is that it’s something inherent, a glitch in the way our brains process information. Another is that it’s a side effect of living, as the majority of humans do, in a world of exchange and markets.

The capuchin study suggests that it’s the latter: Human beings have internalized the socially constructed idea that prices reflect quality, or at least signal desirability. Often, of course, they do. But sometimes they don’t. Sometimes a strong preference for a particular flavor of colored liquid, just because it costs more, is simply ridiculous.

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