Sex, Empathy, Jealousy: How Emotions And Behavior Of Other Primates Mirror Our Own

When Frans de Waal started studying nonhuman primates, in the Netherlands more than 40 years ago, he was told not to consider the emotions of the animals he was observing.

“Thoughts and feelings — the mental processes basically — were off limits,” he says. “We were told not to talk about them, because they were considered by many scientists as ‘inner states’ and you only were allowed to talk about ‘outer states.’ ”

But over the course of his career, de Waal became convinced that primates and other animals express emotions similar to human emotions. He’s now the director of the Living Links Center at the Yerkes National Primate Research Center in Atlanta, where his office window looks out on a colony of chimps.