100 YEARS OLD AND STILL MONKEYING AROUND...

DO APES know what we are thinking? Will they try to put us right if we’re wrong about something? Those questions are addressed in a paper (“Great apes distinguish true from false beliefs in an interactive helping task”) covering research conducted with apes from Leipzig Zoo and published this month in the online science journal Plos One.

The study included 23 chimpanzees, five bonobos and six orangutans all in their late teens or early 20s and the main object was to determine their attitudes to false beliefs in humans.

The basic experiment had two actors playing the roles of experimenter and assistant. At the start, two empty boxes were placed on a table. The Experimenter then, in full view of the assistant and the apes, placed a bunch of keys in one of the boxes, closed and locked it, then left the room. When he was gone, the assistant unlocked the box with the keys in it, took them out and put them in the other box. He then locked both boxes.

The experimenter then returns and tries to unlock the now empty box he had put the keys in, but after some rather cack-handed attempts to open it, he gives up, looks disappointed and shrugs at the apes.

The apes, which have been trained to open the boxes, and have been rewarded with grapes when they do so, not unnaturally want to help but the question is: which box do they open? Is it the one which the experimenter has been trying or the other one which the assistant has sneakily moved the keys to? The results show that more often than not, the apes realised that the experimenter was acting on a false belief and helpfully opened the box containing the keys. Apparently oneyear-old babies can do this, too, but does this really show that apes are just as good as babies in detecting false beliefs or is there another explanation?

I was particularly intrigued by one line in the paper which reported that “six additional chimpanzees and two bonobos ... had to be dropped from the study because they failed the training criterion ... and one additional bonobo was trained but had to be dropped because he could not be separated from the group for testing.” Might this, I wondered, have affected the results? I accordingly questioned some of the rejected apes.

The bonobo who would not leave the group said: ”Why should I? I’m having a great time with my friends and saw no reason to go off and play with these psychologists. They look like jobbing actors to me anyway.”

Two of the chimpanzees said: “What’s the point? I gave up grapes for Lent,” and one other said, “I don’t like grapes anyway so why bother?”

Two bonobos and one chimp said: “Are they kidding? We’re expected to read minds, act helpfully and unlock boxes, and all we get at the end is a grape. I’d have thought a good dinner and a night at the opera would have been appropriate or at least a ticket to another Planet Of The Apes remake.”

The others thought the experimenter was plain daft leaving the assistant all alone with the boxes. Further research is clearly needed.