Those Lying Apes

Apes like to deceive, too--but do they dislike being deceived?

Posted Dec 13, 2011

But it's not only males who deceive in order to get away with sex that is forbidden by the socially-powerful. In his book Chimpanzee Politics (1982), primatologist Frans De Waal writes of Orr, an adolescent female at Arnheim, who would scream while she was having sex. During sneaked copulations with younger males, however, her screams sometimes caught the attention of the alpha, who would do his mighty best to interrupt the couple. Eventually, Orr learned to suppress her vocalizations when mating with lower-ranking males, while she continued the habit of screaming whenever she mated with the alpha.

Competition often motivates individuals to deceive in order to get what they want, whether it's sex, power, or food. Once at Arheim, the chimpanzees all observed the arrival of a box of grapefruit. While they were locked in their sleeping quarters, however, primatologist de Waal brought the box out into the public area and buried the grapefruit in sand. He left a small portion of each grapefruit still uncovered by the sand, just enough for a very observant chimpanzee to notice. After the fruit had been buried, the researcher walked past the chimps with the empty box, and so--understanding what that meant--when they were released from their night cages, they raced off in search of the fruit. Several rushed and scrambled right past the place where the special treats had been buried in sand, but none paused to examine that area carefully. Later on that day, however, as the chimps were relaxing during their regular afternoon siesta, a young male who had been among the group that earlier rushed past the buried grapefruit, now quietly raised himself from his relaxed sprawl, casually strolled over to where the grapefruit had been hidden--away from the gaze of his relaxing fellows--and dug out the fruit and consumed it at his leisure.

We often use deceit to cover some other moral failure, but one distinctive thing about human lying is that we understand that the lie itself is wrong. Lies confuse others, inhibit others, hurt others, and so we understand that lies are anti-social and belong on the list of anti-social moral vices. Other people usually expect the truth, after all, and when we violate their expectation, we've done a wrong thing that is sometimes worse than the bad behavior we were trying to conceal in the first place. That, at least, is the wisdom imparted by our mothers when they said, "I don't mind that you took the cookie from the cookie jar half as much as I mind that you lied to me about it."

Chimpanzees often deceive each other and their human caretakers, that much is clear, but is it also true that chimpanzees, like our own mothers, dislike being deceived? No one has thought to ask this question, and, in any case, it would be a hard one to study experimentally, so I will conclude this post with a simple story on the subject as recollected by Frans X. Plooij, a primatologist at the International Research Institute on Infant Studies in the Netherlands. (You can find this tale in PT blogger Marc Bekoff's collection, The Smile of a Dolphin.)

Like several prominent primatologists of his generation, Plooij was first trained in field research at Jane Goodall's research site in Tanzania, where he studied the group of chimpanzees already made famous by Goodall's early work. As Plooij recalls, at Gombe all researchers were forbidden from interacting in any way with the chimps. The reasons for that rule were obvious. Interaction could affect the research results, so it was bad science. Interaction could also endanger the chimps, who are capable of contracting virtually every infectious human disease. Finally, it could endanger the people, both through disease transmission and also through plain physical damage, should the chimps ever appreciate how remarkably weak people are. When the chimpanzees made any attempt to interact with researchers, therefore, they were instructed, in Plooij's words, "to act like pillars of salt."

Plooij had spent more than a year watching and assessing the behavior of the adult female Passion and her infant Prof. At the same time, Prof's oldest sister, Pom, could never be avoided, since she was still young enough to spend all day near her mother. The chimps weren't usually interested in people, and the people had been instructed to act as if they were uninterested in the chimps, so all this scientific observation took place as if an invisible wall separated the watchers from the watched.

One day, however, Pom tried to reach through that invisible wall. Pom approached the young man and began stroking and poking her fingers into his hair. She was trying to groom him, which is a friendly thing to do among chimps. Plooij was astonished but also pleased. He found the sensation of Pom's soft touch in his hair to be "wonderful," and he was tempted to groom her in return. But, of course, that would break the rule against interaction. No, to be a proper scientist, to protect himself and the chimps, Plooij knew he had to keep that invisible wall intact, and so he acted as if nothing had changed. He remained motionless, unresponding. What else could he do?

Pom, however, continued trying to groom this stange, stubborn ape.

Plooij was now distressed, since it wasn't clear how he could rid himself of Pom. Then he had an inspiration. He remembered how Passion had once managed to discourage a similar kind of pestering behavior by young Flint. Flint had one time been interested in touching Pom's baby Prof. Indeed, Flint spent most of an entire day persistently approaching Passion and reaching out to touch the baby; and Passion, who seemed upset and annoyed, could only turn her back to Flint and clutch her baby defensively. In other circumstances, a mother might not put up with this sort of harassment, but Flint was the son of the socially-powerful female Flo, so Passion was probably reluctant to smack or chase away Flint because she feared an enraged mama Flo. In any case, near the end of the day, Passion finally came up with a brilliant method for getting rid of pesty Flint. She simply stood up and gazed with dramatic intensity at a distant spot, seemingly watching some especially provocative far-away event.

Flint took the bait. He began gazing into the distance as well, as if trying to figure out what Passion saw that was so interesting. Soon, Flint was moving towards the imagined event, and the second he had moved out of her line of vision, Pom, clutching Prof, just took off in the opposite direction.

So the young researcher, now remembering this clever little trick done by Passion to get rid of Flint, decided he would use the same method to get rid of pestery Pom. He pretended that he had suddenly discovered some astonishing event in the distance. He looked up, gazed intently, even moved his head a little from side to side as if focusing his sight acutely. And it worked! Soon Pom had stopped trying to groom Plooij and was looking in the same direction he was. Pom then walked tentatively a short distance toward the imagined point of interest, looked back at Plooij, who continued gazing. Finally, the young chimp decisively moved off and out of sight, headed into the forest in the direction of that imaginary event--and so the researcher was at last able to return, unimpeded, to his observations of Passion and Prof.

A short while later, though, Pom came back, marched directly up to Plooij, and slapped him sharply on the head. Then, for the remainder of the day, she pointedly avoided him.

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