Are We Smart Enough to Know How Smart Animals Are

by Frans de Waal

  Tinbergen’s lecture reminded me of all the great things he had done, which included animal cognition, even though he never used the term. He had worked on how digger wasps find their nest back after a trip away. Also known as beewolves, these wasps capture and paralyze a honeybee, drag it to their nest in the sand (a long burrow), and leave it as a meal for their larvae. Before they go out to hunt for a bee, they make a brief orientation flight to memorize the location of their inconspicuous burrow. Tinbergen put objects around the nest, such as a circle of pinecones, to see what information they used to find it back. He was able to trick the wasps, making them search at the wrong location, by moving his pinecones around.48 His study addressed problem solving tied to a species’ natural history, precisely the topic of evolutionary cognition. The wasps proved very good at this particular task.

  Brainier animals have less restricted cognition and often find solutions to novel or unusual problems. The ending of my grapefruit story with the chimpanzees offers a nice demonstration. After releasing the apes onto the island, a number of them passed over the site where we had hidden the fruits under the sand. Only a few small yellow patches were visible. Dandy, a young adult male, hardly slowed down when he ran over the place. Later in the afternoon, however, when all the apes were dozing off in the sun, he made a beeline for the spot. Without hesitation, he dug up the fruits and devoured them at his leisure, which he would never have been able to do had he stopped right when he saw them. He would have lost them to dominant group mates.49

  Here we see the entire spectrum of animal cognition, from the specialized navigation of a predatory wasp to the generalized cognition of apes, which allows them to handle a great variety of problems, including novel ones. What struck me most is that Dandy at his first passing didn’t linger for a second. He must have made an instant calculation that deception was going to be his best bet.

  3 COGNITIVE RIPPLES

  Eureka!

  The sunny, breezy Canary Islands are about the last place in the world where one would expect a cognitive revolution, yet this is where it all began. In 1913 the German psychologist Wolfgang Köhler came to Tenerife, off the coast of Africa, to head the Anthropoid Research Station, where he remained until after World War I. Even though rumor has it that his job was to spy on passing military vessels, Köhler devoted most of his attention to a small colony of chimpanzees.

  Having eluded indoctrination in the learning theories of his day, Köhler was refreshingly open-minded about animal cognition. Instead of trying to control his animals to seek specific outcomes, he had a wait-and-see attitude. He presented them with simple challenges to find out how they’d meet them. For his most talented chimpanzee, Sultan, he would put a banana out of reach on the ground and offer him sticks that were too short to reach the fruit. Or he would hang a banana high up in the air and spread large wooden boxes around, none of which was tall enough for the purpose. Sultan would first jump or throw things at the banana or drag humans by the hand toward it in the hope that they’d help him out, or at least be willing to serve as a footstool. If this failed, he would sit around for a while without doing anything until he might hit at a sudden solution. He would jump up to put one bamboo stick inside another, making a longer stick. Or he would stack boxes on top of one another so as to build a tower that allowed him to reach the banana. Köhler described this moment as the “aha! experience,” as if a lightbulb had been switched on, not unlike the story of Archimedes, who jumped out of his bath in which he had discovered how to measure the volume of submerged objects, after which he ran naked through the streets of Syracuse, shouting “Eureka!”

  Grande, a female chimpanzee, piles up four boxes to reach a banana. A century ago Wolfgang Köhler set the stage for animal cognition research by demonstrating that apes can solve problems in their heads by means of a flash of insight, before enacting the solution.

  According to Köhler, a sudden insight explained how Sultan put together what he knew about bananas, boxes, and sticks to produce a brand-new action sequence that would take care of his problem. The scientist ruled out imitation and trial-and-error learning, since Sultan had had no previous experience with these solutions nor ever been rewarded for them. The outcome was “unwaveringly purposeful” action in which the ape kept trying to reach his goal despite the numerous stacking errors resulting in the collapse of his towers. A female, Grande, was an even more undeterred and patient architect who once built a wobbly tower of four boxes. Köhler remarked that once a solution was discovered, the apes found it easier to solve similar problems, as if they had learned something about the causal connections. He described his experiments in admirable detail in The Mentality of Apes in 1925, which was at first ignored and then disparaged, but that now stands as a classic in evolutionary cognition.1

  The insightful solutions of Sultan and other apes hint at the kind of mental activity that we refer to as “thinking,” even though its precise nature was (and still is) barely understood. A few years later the American primate expert Robert Yerkes described similar solutions.

  Frequently I have seen a young chimpanzee, after trying in vain to get its reward by one method, sit down and reexamine the situation as though taking stock of its former efforts and trying to decide what to do next. . . . More startling by far than the quick passage from one method to another, the definiteness of acts, or the pauses between efforts, is the sudden solution of problems. . . . Frequently, although not in all individuals or in all problems, correct and adequate solution is achieved without warning and almost instantly.2

  Yerkes went on to note that those who only know animals that are good at trial-and-error learning “can scarcely be expected to believe” his descriptions. He thus anticipated the inevitable pushback to these revolutionary ideas. Unsurprisingly, it arrived in the form of trained pigeons shoving little boxes around in a dollhouse so that they could stand on top of them to reach a tiny plastic banana associated with grain rewards.3 How entertaining! At the same time, Köhler’s interpretations were criticized as anthropomorphic. But I heard an amusing antidote to these accusations from an American primatologist brave enough to enter the Skinnerian lion’s den in the 1970s, where he debated tool-using apes.

  Without offering specifics, Emil Menzel told me that an eminent East Coast professor once invited him to speak. This professor looked down on primate research and was openly hostile to cognitive interpretations, two orientations that often go together. Perhaps he invited young Menzel to make fun of him, not realizing that the tables might be turned. Menzel treated his audience to spectacular footage of his chimpanzees putting a long pole against their enclosure’s high wall. While some individuals held the pole steady, others scaled it to reach temporary freedom. It was a complex operation since the apes needed to avoid coils of electrified wire while recruiting one another’s assistance at critical moments through hand gestures. Menzel, who had filmed all this himself, decided to run his footage without mentioning intelligence. He was going to be as neutral as possible. His narration was purely descriptive: “You now see Rock grab the pole while glancing at the others,” or “Here a chimpanzee swings over the wall.”4

  After his lecture, the professor jumped up to accuse Menzel of being unscientific and anthropomorphic, of attributing plans and intentions to animals that obviously had neither. To a roar of approval, Menzel countered that he had not attributed anything. If this professor had seen plans and intentions, he must have seen them with his own eyes, because Menzel himself had refrained from suggesting any such things.

  Interviewing Menzel at my home (he lived nearby) a few years before his death, I took the opportunity to ask him about Köhler. Widely recognized as a great expert on great apes himself, Menzel said it had taken him years working with chimps to fully appreciate this pioneer’s genius. Like Köhler, Menzel believed in watching over and over and thinking through what his observations might mean, even if he’d seen a certain behavior only once. He protested against labeling a single observation an �
��anecdote,” adding with a mischievous smile, “My definition of an anecdote is someone else’s observation.” If you have seen something yourself and followed the entire dynamic, there usually is no doubt in your mind of what to make of it. But others may be skeptical and need convincing.

  Here I cannot resist telling an anecdote of my own. And I do not mean The Great Escape at Burgers’ Zoo, where the chimpanzee colony did exactly what Menzel had documented. After twenty-five apes raided the zoo’s restaurant, we found a tree trunk, far too heavy for a single ape to carry, propped against the inside wall of their enclosure. No, I mean an insightful solution to a social problem—a sort of social tool use—that is my specialty. Two female chimps were sitting in the sun, with their children rolling around in the sand in front of them. When the play turned into a screaming, hair-pulling fight, neither mother knew what to do because if one of them tried to break up the fight, it was guaranteed that the other would protect her offspring, since mothers are never impartial. It is not unusual for a juvenile quarrel to escalate into an adult fight. Both mothers nervously monitored each other as well as the fight. Noticing the alpha female, Mama, asleep nearby, one of them went over to poke her in the ribs. As the old matriarch got up, the mother pointed at the fight by swinging an arm in its direction. Mama needed only one glance to grasp what was going on and took a step forward with a threatening grunt. Her authority was such that this shut up the youngsters. The mother had found a quick and efficient solution to her problem, relying on the mutual understanding typical of chimpanzees.

  Similar understanding can be seen in their altruism, such as when younger females collect water in their mouths for an aging female, who can barely walk anymore, spitting it into her open mouth so that she doesn’t have to walk all the way to the spigot. The British primatologist Jane Goodall described how Madame Bee, a wild chimpanzee, had become too old and weak to climb into fruiting trees. She would patiently wait at the bottom for her daughter to carry down fruits, upon which the two of them would contentedly munch together.5 In such cases, too, apes grasp a problem and come up with a fresh solution, but the striking part here is that they perceive another ape’s problem. Since these social perceptions have attracted much research, we’ll delve into them later on, but let me clarify one general point about problem solving. Although Köhler stressed that trial-and-error learning could not explain his observations, it was not as if learning played no role at all. In fact, his apes committed tons of “stupidities,” as Köhler called them, that showed that solutions were rarely perfectly formed in their minds and required quite a bit of tweaking.

  His apes had undoubtedly learned the affordances of various items. This term from cognitive psychology refers to how objects can be used, such as the handle on a teacup (which affords holding) or the steps on a ladder (which afford climbing). Sultan must have known the affordances of sticks and boxes before he hit on his solutions. Similarly, the female chimp who activated Mama had no doubt witnessed the latter’s effectiveness as arbitrator. Insightful solutions invariably rest on prior information. What is special about apes is their capacity to flexibly weave such preexisting knowledge into new patterns, never tried before, that work to their advantage. I have speculated the same about their political strategies, such as the way chimps will isolate a rival from his supporters or encourage a truce by dragging reluctant former combatants toward each other.6 In all such cases, we see apes finding insightful solutions to everyday problems. They are so good at it that even the staunchest skeptic, as Menzel discovered, finds it impossible to watch them without being struck by their obvious intentionality and intelligence.

  Wasp Mugs

  There was a time when scientists thought behavior derived from either learning or biology. Human behavior was on the learning side, animal behavior on the biology side, and there was little in between. Never mind the false dichotomy (in all species, behavior is a product of both), but increasingly a third explanation had to be added: cognition. Cognition relates to the kind of information an organism gathers and how it processes and applies this information. Clark’s nutcrackers remember where they have stored thousands of nuts, beewolves make an orientation flight before leaving their burrow, and chimpanzees nonchalantly learn the affordances of play objects. Without any reward or punishment, animals accumulate knowledge that will come in handy in the future, from finding nuts in the spring, to returning to one’s burrow, to reaching a banana. The role of learning is obvious, but what is special about cognition is that it puts learning in its proper place. Learning is a mere tool. It allows animals to collect information in a world that, like the Internet, contains a staggering amount of it. It is easy to drown in the information swamp. An organism’s cognition narrows down the information flow and makes it learn those specific contingencies that it needs to know given its natural history.

  Many animals have cognitive achievements in common. The more scientists discover, the more ripple effects we notice. Capacities that were once thought to be uniquely human, or at least uniquely hominoid (the tiny primate family of humans plus apes), often turn out to be widespread. Traditionally, apes have been the first to inspire discoveries thanks to their manifest intellect. After the apes break down the dam between humans and the rest of the animal kingdom, the floodgates often open to include species after species. Cognitive ripples spread from apes to monkeys to dolphins, elephants, and dogs, followed by birds, reptiles, fish, and sometimes invertebrates. This historical progression is not to be confused with a scale with Hominoids on top. I rather view it as an ever-expanding pool of possibilities in which the cognition of, say, the octopus may be no less astonishing than that of any given mammal or bird.

  Paperwasps live in small hierarchical colonies in which it pays to recognize every individual. Their black-and-yellow facial markings allow them to tell one another apart. A closely related wasp species with a less differentiated social life lacks face recognition, which shows how much cognition depends on ecology.

  Consider face recognition, which was initially viewed as uniquely human. Now apes and monkeys have joined the countenance elite. Every year when I visit Burgers’ Zoo, in Arnhem, a few chimps still remember me from more than three decades before. They pick out my face from the crowd, greeting me with excited hooting. Not only do primates recognize faces, but faces are special to them. Like humans, they show an “inversion effect”: they have trouble recognizing faces that are turned upside down. This effect is specific for faces; how an image is oriented hardly matters for the recognition of other objects, such as plants, birds, or houses.

  When we tested capuchin monkeys using touchscreens, we noticed that they freely tapped all sorts of images, but they freaked out at the first face that appeared. They clutched themselves and whined, reluctant to touch the picture. Did they treat it with more respect because putting a hand on a face violates a social taboo? Once they got over their hesitation, we showed them portraits of group mates and unknown monkeys. All these portraits look alike to naïve humans since they concern the same species, but our monkeys had no trouble telling them apart, indicating with a little tap on the screen which ones they knew and which ones they didn’t.7 We humans take this ability for granted, but the monkeys had to link a two-dimensional pattern of pixels to a live individual in the real world, which they did. Face recognition, science concluded, is a specialized cognitive skill of primates. But no sooner had it done so than the first cognitive ripples arrived. Face recognition has been found in crows, sheep, even wasps.

  It is unclear what faces mean to crows. In their natural lives, they have so many other ways of recognizing one another by calls, flight patterns, size, and so on, that faces may not be relevant. But crows have incredibly sharp eyes, so they likely notice that humans are easiest recognized by their faces. Lorenz reported harassment of certain people by crows and was so convinced of their ability to hold a grudge that he disguised himself with a costume whenever he captured and banded his jackdaws. (Both jackdaws and crows are co
rvids, a brainy bird family that also includes jays, magpies, and ravens.) Wildlife biologist John Marzluff at the University of Washington, in Seattle, has captured so many crows that these birds take his name in vain whenever he walks around, scolding and dive-bombing him, doing justice to the “murder” label used for a whole bunch of them.

  We don’t know how they pick us out of the forty thousand folk scurrying like two-legged ants over well-worn trails. But single us out they do, and nearby crows flee while uttering a call that sounds to us like vocal disgust. In contrast, they calmly walk among our students and colleagues who have never captured, measured, banded, or otherwise humiliated them.8

  Marzluff set out to test this recognition with rubber face masks like those we put on at Halloween. After all, crows may recognize certain people by their bodies, hair, or clothes, but with masks you can move a human “face” around from one body to the next, isolating its specific role. His angry birds experiment involved capturing crows while wearing a particular mask, then have coworkers walk around with either this mask or a neutral one. The crows easily remembered the mask of the capturer, far from fondly. Funny enough, the neutral mask was Vice President Dick Cheney’s face, which elicited more negative reactions from the students on campus than from the crows. Not only did birds that had never been captured recognize the “predator” mask, but years later they still harassed its wearers. They must have picked up on the hateful response of their fellows resulting in massive distrust of specific humans. As Marzluff explains, “It would be a rare hawk that would be nice to a crow, but with humans you have to classify us as individuals. Clearly, they’re able to do that.”9