The Monkeys Are Revolting!

In a study involving the exchange of tokens for food, Capuchin monkeys who got lesser treats than other Capuchins did basically went on strike and refused to continue "working." Karen Hopkin reports.

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Those clever little monkeys are on strike again. And I don’t mean the Writers Guild. No, I’m talking about the tufted capuchin monkeys at Yerkes Primate Research Center. Those headstrong primates have put down their feet—all four of ‘em—and refused to work for unfair wages. Their grievances are presented in the current online edition of the Proceedings of the National Academy of Sciences.

To examine capuchins’ sense of fairness, Frans de Waal and his colleagues at Emory University designed a bartering task in which monkeys are given tokens they can then exchange for food. Some monkeys get a plain old cucumber slice, others get a coveted grape. What the researchers discovered is that when monkeys who get salad fixins see their friends get fruit, they basically refuse to play anymore.

But were the monkeys really reacting to inequity, thinking, “That’s not fair: She got a grape and I didn’t”? Or were they just being greedy? “I see grapes. I want one.” Or maybe they’re frustrated. “Last time I got a grape—now this?”  The current study suggests that the grapeless monkeys indeed consider themselves shortchanged. Tests to see what they might type given an infinite amount of time are on hold until both labor disputes are settled.

—Karen Hopkin

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