Are We Smart Enough to Know How Smart Animals Are? (8 page)

The first counterattack came from B. F. Skinner and colleagues, who promptly trained pigeons to peck at dots on themselves while standing in front of a mirror.
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Reproducing a semblance of the behavior, they felt, would solve the mystery. Never mind that it took them hundreds of grain rewards to get the pigeons to do something that chimpanzees and humans do without any coaching. One can train goldfish to play soccer and bears to dance, but does anyone believe that this tells us much about the skills of human soccer stars or dancers? Worse, we aren’t even sure that this pigeon study is replicable. Another research team spent years trying the exact same training, using the same strain of pigeon, without producing any self-pecking birds. They ended up publishing a report critical of the original study with the word
Pinocchio
in its title.
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The second counterattack was a fresh interpretation of the mirror test, suggesting that the observed self-recognition might be a by-product of the anesthesia used in the marking procedure. Perhaps when a chimpanzee recovers from the anesthesia, he randomly touches his face, resulting in accidental contact with the mark.
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This idea was quickly disproved by another team that carefully recorded which facial areas chimpanzees touch. It turned out that the touching is far from random: it specifically targets the marked area and peaks right after the ape has seen his own reflection.
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This was, of course, what the experts had been saying all along, but now it was official.

Apes really don’t need anesthesia to show how well they understand mirrors. They spontaneously use them to look inside their mouth, and females always turn around to check out their behinds—something males don’t care about. Both are body parts that they normally never get to see. Apes also use mirrors for special needs. For example, Rowena has a little injury on the top of her head caused by a scuffle with a male. Immediately, when we hold up a mirror, she inspects the injury and grooms around it while following the reflection of her movements. Another female, Borie, has an ear infection that we are trying to treat with antibiotics, but she keeps waving her hand in the direction of a table that is empty except for a small plastic mirror. It takes a while before we understand her intentions, but as soon as we hand her the toy, she picks up a straw and angles the mirror such that she can clean out her ear while watching the process in the mirror.

B. F. Skinner was more interested in experimental control over animals than spontaneous behavior. Stimulus-response contingencies were all that mattered. His behaviorism dominated animal studies for much of the last century. Loosening its theoretical grip was a prerequisite for the rise of evolutionary cognition.

A good experiment doesn’t create new and unusual behavior but taps into natural tendencies, which is exactly what Gallup’s test did. Given the apes’ spontaneous mirror use, no expert would ever have come up with the anesthesia story. So what makes scientists unaccustomed to primates think they know better? Those of us who work with exceptionally gifted animals are used to unsolicited opinions about how we ought to test them and what their behavior actually means. I find the arrogance behind such advice mind-boggling. Once, in his desire to underscore the uniqueness of human altruism, a prominent child psychologist shouted at a large audience, “No ape will ever jump into a lake to save another!” It was left to me to point out during the Q&A afterward that there are actually a handful of reports of apes doing precisely this—often to their own detriment, since they don’t swim.
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The same arrogance explains the doubts raised about one of the best-known discoveries in field primatology. In 1952 the father of Japanese primatology, Kinji Imanishi, first proposed that we may justifiably speak of animal culture if individuals learn habits from one another resulting in behavioral diversity between groups.
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By now fairly well accepted, this idea was so radical at the time that it took Western science forty years to catch up. In the meantime, Imanishi’s students patiently documented the spreading of sweet potato washing by Japanese macaques on Koshima Island. The first monkey to do so was a juvenile female, named Imo, now honored with a statue at the entrance to the island. From Imo the habit spread to her age peers, then to their mothers, and eventually to nearly all monkeys on the island. Sweet potato washing became the best-known example of a learned social tradition, passed on from generation to generation.

Many years later, this view triggered a so-called
killjoy account
—an attempt to deflate a cognitive claim by proposing a seemingly simpler alternative—according to which the monkey-see-monkey-do explanation of Imanishi’s students was overblown. Why couldn’t it just have been individual learning—that is, each monkey acquired potato washing on its own without the assistance of anybody else? There might even have been human influence. Perhaps potatoes were handed out selectively by Satsue Mito, Imanishi’s assistant, who knew every monkey by name. She may have rewarded monkeys who dipped their spuds in the water, thus prompting them to do so ever more frequently.
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The only way to find out was to go to Koshima and ask. Having been twice to this island in the subtropical south of Japan, I had a chance to interview the then eighty-four-year-old Mrs. Mito via an interpreter. She reacted with incredulity to my question about food provisioning. One cannot hand out food any way one wants, she insisted. Any monkey that holds food while high-ranking males are empty-handed risks getting into trouble. Macaques are very hierarchical and can be violent, so putting Imo and other juveniles before the rest would have endangered their lives. In fact, the last monkeys to learn potato washing, the adult males, were the first ones to be fed. When I brought up the argument to Mrs. Mito that she might have rewarded washing behavior, she denied that this was even possible. In the early years, potatoes were handed out in the forest far away from the freshwater stream where the monkeys did their cleaning. They’d collect their spuds and quickly run off with them, often bipedally since their hands were full. There was no way for Mito to reward whatever they did in the distant stream.
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But perhaps the strongest argument for social as opposed to individual learning was the way the habit spread. It can hardly be coincidental that one of the first to follow Imo’s example was her mother, Eba. After this, the habit spread to Imo’s peers. The learning of potato washing nicely tracked the network of social relations and kinship ties.
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The first evidence for animal culture came from sweet-potato-washing Japanese macaques on Koshima Island. Initially, the washing tradition spread among same-aged peers, but nowadays it is propagated transgenerationally, from mother to offspring.

Like the scientist who gave us the mirror-anesthesia hypothesis, the one who wrote an entire article debunking the Koshima discovery was a nonprimatologist who, moreover, never bothered to set foot on Koshima or check his ideas with the fieldworkers who had camped for decades on the island. Again, I can’t help but wonder about the mismatch between conviction and expertise. Perhaps this attitude is a leftover of the mistaken belief that if you know enough about rats and pigeons, you know everything there is to know about animal cognition. It prompts me to propose the following know-thy-animal rule:
Anyone who wishes to stress an alternative claim about an animal’s cognitive capacities either needs to familiarize him- or herself with the species in question or make a genuine effort to back his or her counterclaim with data
. Thus, while I admire Pfungst’s work with Clever Hans and its eye-opening conclusions, I have great trouble with armchair speculations devoid of any attempt to check their validity. Given how seriously the field of evolutionary cognition takes variation between species, it is time to respect the special expertise of those who have devoted a lifetime getting to know one of them.

The Thaw

One morning at Burgers’ Zoo, we showed the chimpanzees a crate full of grapefruits. The colony was in the building where it spends the night, which adjoins a large island, where it spends the day. The apes seemed interested enough watching us carry the crate through a door onto the island. When we returned to the building with an empty crate, however, pandemonium broke out. As soon as they saw that the fruits were gone, twenty-five apes burst out hooting and hollering in a most festive mood, slapping one another’s backs. I have never seen animals so excited about
absent
food. They must have inferred that grapefruits cannot vanish, hence must have remained on the island onto which the colony would soon be released. This kind of reasoning does not fall into any simple category of trial-and-error learning, especially since it was the first time we followed this procedure. The grapefruit experiment was a one-time event to study responses to cached food.

One of the first tests of
inferential reasoning
was conducted by American psychologists David and Ann Premack, who presented Sadie, a chimpanzee, with two boxes. They placed an apple in one and a banana in the other. After a few minutes of distraction, Sadie saw one of the experimenters munching on either an apple or a banana. This experimenter then left, and Sadie was released to inspect the boxes. She faced an interesting dilemma, since she had not seen how the experimenter had gotten his fruit. Invariably, Sadie would go to the box with the fruit that the experimenter had
not
eaten. The Premacks ruled out gradual learning, because Sadie made this choice on the very first trial as well as all subsequent ones. She seemed to have reached two conclusions. First, that the eating experimenter had removed his fruit from one of the two boxes, even if she had not actually seen him do so. And second, that this meant that the other box must still hold the other fruit. The Premacks note that most animals don’t make any such assumptions: they just see an experimenter consume fruit, that’s all. Chimpanzees, in contrast, try to figure out the order of events, looking for logic, filling in the blanks.
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Years later the Spanish primatologist Josep Call presented apes with two covered cups. They had learned that only one would be baited with grapes. If Call removed the tops and let them look inside the cups, the apes chose the one with grapes. Next, he kept the cups covered and shook first one, then the other. Only the cup with grapes made noise, which was the one they preferred. This was not too surprising. But making things harder, Call would sometimes shake only the empty cup, which made no noise. In this case, the apes would still pick the other one, thus operating on the basis of exclusion. From the absence of sound, they guessed where the grapes must be. Perhaps we are not impressed by this either, as we take such inferences for granted, but it is not all that obvious. Dogs, for example, flunk this task. Apes are special in that they seek logical connections based on how they believe the world works.
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Here it gets interesting, because aren’t we supposed to go for the simplest possible explanation? If large-brained animals, such as apes, try to get at the logic behind events, could this be the simplest level at which they operate?
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It reminds me of Morgan’s provision to his canon, according to which we are allowed more complex premises in the case of more intelligent species. We most certainly apply this rule to ourselves. We always try to figure things out, applying our reasoning powers to everything around us. We go so far as to invent causes if we can’t find any, leading to weird superstitions and supernatural beliefs, such as sports fans wearing the same T-shirt over and over for luck, and disasters being blamed on the hand of God. We are so logic-driven that we can’t stand the absence of it.

Evidently, the word
simple
is not as simple as it sounds. It means different things in relation to different species, which complicates the eternal battle between skeptics and cognitivists. In addition, we often get tangled up in semantics that aren’t worth the heat they generate. One scientist will argue that monkeys understand the danger posed by leopards, whereas another will say that monkeys have merely learned from experience that leopards sometimes kill members of their species. Both statements are really not that different, even though the first uses the language of understanding, and the second of learning. With the decline of behaviorism, debates on these issues have fortunately grown less fiery. By attributing all behavior under the sun to a single learning mechanism, behaviorism set up its own downfall. Its dogmatic overreach made it more like a religion than a scientific approach. Ethologists loved to slam it, saying that instead of domesticating white rats in order to make them suitable to a particular testing paradigm, behaviorists should have done the opposite. They should have invented paradigms that fit “real” animals.