Do chimps perceive other minds?

"Now , determining whether a chimp has thoughts about others’ thoughts is a rather tricky research question . But Povinelli had some ingenious ways of going about it . For example, in a famous series of experiments published as a monograph titled What Young Chimpanzees Know about Seeing (1996), Povinelli trained his group of seven apes to come into the lab one at a time, reach their arms through a hole in a Plexiglas partition , and beg for a food reward from one of two human experimenters. There were two holes, one in front of each of the two experimenters, respectively . If the chimps reached out to person A, then person A would hand them the treat . If the chimps reached out to person B, person B would give it to them instead. But the chimps got only one choice between these two experimenters before the next trial began and the chimp next in line made its own selection .

After the animals got the gist of this simple game, the real experiment began . The rules remained the same—again , reach through one of the holes to get that person to fetch your treat—but now when the chimp entered the lab, it saw one of the experimenters wearing a blindfold, or with her back turned, her eyes closed, or even wearing a bucket over her head. The other experimenter , meanwhile, had her eyes wide open and was watching the chimp attentively .

If you’re thinking like an experimental psychologist , then the purpose of the study should at this point be jumping out at you . Povinelli hypothesized that if chimpanzees have a theory of mind, well then they should quite clearly pick the person who can see them over the one who can’t . After all , picking the unsighted experimenter would leave the chimp without its prize because—being unable to see the chimp’s gesture toward her—this person can’t possibly know she has been chosen . The point is that to avoid making the wrong choice, the animal must take the perspective of the person , or at least attribute the mental state of “not seeing” to her.

Povinelli and his coauthor , Timothy Eddy , surprised almost every one when they found that the chimps failed to show a preference between the two experimenters. By contrast , in a similar game, even two-year-old children showed a clear preference for the sighted person . Other cleverly designed studies followed, by both Povinelli and others, all presumably showing that , contrary to what we had been led to believe by the “visual rhetoric” of those Goodall-esque documentaries, chimps aren’t entirely like us after all ; in particular , they lack a theory of mind and fail to reason about what others see, know, feel , believe, or intend."