Read Are We Smart Enough to Know How Smart Animals Are? Online
Authors: Frans de Waal
One area of cognitive research that has been lucky to escape the species barrier is the study of ToM in animals that are so different from us that everyone understands that humans are unsuitable partners. This has been the case with corvids. Since a true animal watcher never takes a break, the British ethologist Nicky Clayton made a major discovery over lunch at the University of California at Davis. While sitting at an outdoor terrace, she saw Western scrub jays fly off with scraps stolen from the tables. They not only cached them but also guarded them against thieves. If another bird saw where they hid their food, it was bound to disappear. Clayton noticed that after their rivals left the scene, many of the jays returned to rebury their treasures. In follow-up research with Nathan Emery in their lab at Cambridge, she let jays cache mealworms either in private or while being watched by another jay. Given a chance, the jays quickly re-cached their worms at a new location—but only if they had been watched. They seemed to understand that the food was safe if no other birds had any information. Moreover, only birds who themselves had pilfered others’ food re-cached their own. Following the dictum “It takes a thief to know a thief,” the jays seemed to extrapolate from their own criminality to that of others.
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A Western scrub jay caches a mealworm while being watched from behind glass by another. As soon as he is alone, the jay will quickly rehide his treasures, as if realizing that the other knows too much.
Again, we recognize the Menzel-like design of this experiment, which is even more obvious in a study of perspective-taking ravens. The Austrian zoologist Thomas Bugnyar had a low-ranking male who was expert at opening canisters that contained goodies, but this male often lost his prize to a bullying and stealing dominant male. The low-ranking male, however, learned to distract his competitor by enthusiastically opening empty containers and making as if to eat from them. When the dominant bird found out, “he got very angry, and started throwing things around.” Bugnyar further found that when ravens approach hidden food, they take into account what other ravens know. If their competitors have the same knowledge, they hurry to get there first. But if the others are ignorant, they take their time.
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All in all, animals do plenty of perspective taking, from being aware of what others want to knowing what others know. A few frontiers are left, of course, such as whether they recognize when others have the
wrong
knowledge. In humans, researchers test this issue with the so-called false-belief task. But since these refinements are hard to evaluate without language, we face a dearth of animal data. Still, even if the remaining differences hold up, there is little doubt that the blanket assertion that ToM is uniquely human must be downgraded to a more nuanced, gradualist view.
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Humans probably possess a fuller understanding of one another, but the contrast with other animals is not stark enough that extraterrestrials would automatically pick ToM as the chief marker that sets us apart.
While this conclusion is based on solid data from repeated experiments, let me add one anecdote that captures the phenomenon in an entirely different way. At the Yerkes Field Station—where apes live in grassy open-air enclosures in the warm Georgia weather—I developed a special bond with an exceptionally bright female chimp named Lolita. One day Lolita had a new baby, and I wanted to get a good look at it. This is hard to do since a newborn ape is really no more than a little dark blob against its mother’s dark tummy. I called Lolita out of her grooming huddle, high up in the climbing frame, and pointed at her belly as soon as she sat down in front of me. Looking at me, she took the infant’s right hand in her right hand and its left hand in her left hand. It sounds simple, but given that the baby was ventrally clinging to her, she had to cross her arms to do so. The movement resembled that of people crossing their arms when grabbing a T-shirt by its hems in order to take it off. She then slowly lifted the baby into the air while turning it around its axis, unfolding it in front of me. Suspended from its mother’s hands, the baby now faced me instead of her. After it made a few grimaces and whimpers—infants hate to lose touch with a warm belly—Lolita quickly tucked it back into her lap.
With this elegant motion, Lolita demonstrated that she realized I would find the front of her newborn more interesting than its back. To take someone else’s perspective represents a huge leap in social evolution.
Spreading Habits
Decades ago friends of mine were outraged by a newspaper article that ranked the smartest canine breeds. They happened to own the breed that was dead last on the list: the Afghan hound. Naturally, the top breed was the border collie. My insulted friends argued that the only reason Afghans were considered dim-witted is that they are independent-minded, stubborn, and unwilling to follow orders. The newspaper’s list was about obedience, they said, not intelligence. Afghans are perhaps more like cats, which are not beholden to anyone. This is no doubt why some people rate cats as less intelligent than dogs. We know, however, that a cat’s lack of response to humans is not due to ignorance. A recent study showed that felines have no trouble recognizing their owner’s voice. The deeper problem is that they don’t care, prompting the study’s authors to add: “the behavioral aspects of cats that cause their owners to become attached to them are still undetermined.”
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I had to think of this story when dog cognition emerged as a hot topic. Dogs were depicted as smarter than wolves, perhaps even apes, because they paid better attention to human pointing gestures. A human would point at one out of two buckets, and the dog would check that particular bucket out for a reward. Scientists concluded that domestication had given dogs extra intelligence compared to their ancestors. But what does it mean that wolves fail to follow human pointing? With a brain about one-third larger than a dog’s, I bet a wolf could outsmart its domesticated counterpart anytime—yet all we go by is how they react to
us
. And who says that the difference in reaction is inborn, a consequence of domestication, and not based on familiarity with the species doing the pointing? It is the old nature-nurture dilemma. The only way to determine how much of a trait is produced by genes and how much by the environment is to hold one of these two constant to see what
difference
the other one makes. It is a complex problem that is never fully resolved. In the dog-wolf comparison, this would mean raising wolves like dogs in a human household. If they still differ, genetics might be at play.
Raising wolf puppies in the home is a hellish job, though, since they are exceptionally energetic and less rule-bound than dog puppies, chewing up everything in sight. When dedicated scientists raised wolves this way, the nurture hypothesis came out the winner. Human-raised wolves followed hand points as well as dogs. A few differences persisted, though, such as that wolves looked less at human faces than dogs and were more self-reliant. When dogs tackle a problem they cannot solve, they look back at their human companion to get encouragement or assistance—something that wolves never do. Wolves keep trying and trying on their own. Domestication may be responsible for this particular difference. Instead of intelligence, though, it seems more a question of temperament and relations with us—those weird bipedal apes that the wolf evolved to fear and the dog was bred to please.
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Dogs, for example, engage in lots of eye contact with us. They have hijacked the human parental pathways in the brain, making us care about them in almost the same way that we care about our children. Dog owners who stare into their pet’s eyes experience a rapid increase in oxytocin—a neuropeptide involved in attachment and bonding. Exchanging gazes full of empathy and trust, we enjoy a special relationship with the dog.
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Cognition requires attention and motivation, yet it cannot be reduced to either. As we have seen, the same problem troubles the comparison between apes and children, an issue that popped up again in the controversy around animal culture. Whereas in the nineteenth century, anthropologists were still open to the possibility of culture outside our own species, in the twentieth they began to write culture with a capital
C
while claiming that the trait is what makes us human. Sigmund Freud considered culture and civilization a victory over nature, while the American anthropologist Leslie White, in a book ironically entitled
The
Evolution of Culture
, declared: “Man and culture originated simultaneously—this by definition.”
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Naturally, when the first reports of animal culture came along, defined as habits learned from others—from potato-washing macaques and nut-cracking chimpanzees to bubble-net-hunting humpback whales—they faced a wall of hostility. One line of defense against this offensive notion was to focus on the learning mechanism. If it could be shown that human culture relies on distinct mechanisms, so the thinking went, we might be able to claim culture for ourselves. Imitation became the holy grail of this battle.
To this end, the age-old definition of
imitat
ing
as “doing an act from seeing it done” had to be changed to something narrower, something more advanced. The category
true imitation
was born, which requires one individual to intentionally copy another’s specific technique to achieve a specific goal.
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Merely duplicating behavior, such as one songbird learning another’s song, was not enough anymore: it had to be done with insight and comprehension. While imitation is common in lots of animals according to the old definition, true imitation is rare. We learned this fact from experiments in which apes and children were prompted to imitate an experimenter. They’d watch a human model open a puzzle box or rake in food with a tool. While the children copied the demonstrated action, the apes failed, hence the conclusion that other species lack imitative capacities and cannot possibly have culture. The comfort this finding brought to some circles greatly puzzled me, because it did not answer any fundamental questions either about animal culture or about human culture. All it did was draw a flimsy line in the sand.
One can see here the interplay between the redefinition of a phenomenon and the quest to know what sets us apart, but also a deeper methodological problem, because whether apes imitate us or not is wholly beside the point. For culture to arise in a species, all that matters is that its members pick up habits from
one another
. There are only two ways to make a fair comparison in this regard (if we disregard the third option of having white-coated apes administer tests to both apes and children). One is to follow the wolf example: raise apes in a human home so that they are as comfortable as children around a human experimenter. The second is the so-called
conspecific approach
, which is to test a species with models of its own kind.
The first solution yielded results right away, because several human-raised apes turned out to be as good at imitating members of our species as were young children.
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In other words, apes, like children, are born imitators and prefer to copy the species that raised them. Under most circumstances, this will be their own kind, but if reared by another species, they are prepared to imitate that one as well. Using us as models, these apes spontaneously learn to brush their teeth, ride bicycles, light fires, drive golf carts, eat with a knife and fork, peel potatoes, and mop the floor. It reminds me of suggestive stories on the Internet about dogs raised by cats, which show feline behavior such as sitting in boxes, crawling under tight spaces, licking their paws to clean their face, or sitting with their front legs tucked in.
Another critical study was conducted by Victoria Horner, a Scottish primatologist, who later became my team’s lead expert on cultural learning. Together with Andrew Whiten of St. Andrews University, Vicky worked with a dozen orphan chimps at Ngamba Island, a sanctuary in Uganda. She acted like a mix between a mother and caretaker for the juvenile apes. Sitting next to her during tests, the juvenile apes were attached to Vicky and eager to follow her example. Her experiment created waves because as in Ayumu’s case, the apes proved to be smarter than the children. Vicky would poke a stick into holes in a large plastic box, going through a series of holes until a candy would roll out. Only one hole mattered. If the box was made of black plastic, it was impossible to tell that some of the holes were just for show. A transparent box, on the other hand, made it obvious where the candies came from. Handed the stick and the box, young chimps mimicked only the necessary moves, at least with the transparent box. The children, on the other hand, mimicked everything that Vicky had demonstrated, including useless moves. They did so even with the transparent box, approaching the problem more like a magic ritual than as a goal-directed task.
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