Are We Smart Enough to Know How Smart Animals Are Read online

  For Catherine,

  whom I was smart enough to marry

  CONTENTS

  Prologue

  1MAGIC WELLS

  2A TALE OF TWO SCHOOLS

  3COGNITIVE RIPPLES

  4TALK TO ME

  5THE MEASURE OF ALL THINGS

  6SOCIAL SKILLS

  7TIME WILL TELL

  8OF MIRRORS AND JARS

  9EVOLUTIONARY COGNITION

  Notes

  Bibliography

  Glossary

  Acknowledgments

  PROLOGUE

  The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind.

  —Charles Darwin (1871)1

  One early November morning, while the days were getting colder, I noticed that Franje, a female chimpanzee, was gathering all the straw from her bedroom. She took it under her arm out onto the large island at the Burgers’ Zoo, in the Dutch city of Arnhem. Her behavior took me by surprise. First of all, Franje had never done this before, nor had we ever seen other chimps drag straw outside. Second, if her goal was to stay warm during the day, as we suspected, it was notable that she collected the straw while at a cozy temperature inside a heated building. Instead of reacting to the cold, she was bracing for a temperature she could not actually feel. The most reasonable explanation would be that she extrapolated from the previous shivering day to the weather expected today. In any case, later on she stayed nice and warm with little Fons, her son, in the straw nest she’d built.

  I never cease wondering about the mental level at which animals operate, even as I know full well that a single story is not enough to draw conclusions. But those stories inspire observations and experiments that do help us sort out what’s going on. The science fiction novelist Isaac Asimov reportedly once said, “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny.’” I know this thought all too well. We go through a long process of watching our animals, being intrigued and surprised by their actions, systematically testing our ideas about them, and arguing with colleagues over what the data actually mean. As a result, we are rather slow to accept conclusions, and disagreement lurks around every corner. Even if the initial observation is simple (an ape collects a pile of straw), the repercussions can be enormous. The question as to whether animals make plans for the future, as Franje seemed to be doing, is one that science is currently quite preoccupied with. Specialists speak of mental time travel, chronesthesia, and autonoesis, but I will avoid such arcane terminology and try to translate the progress into ordinary language. I will relate stories of the everyday use of animal intelligence as well as offer actual evidence from controlled experiments. The first tells us what purpose cognitive capacities serve, while the second helps us rule out alternative explanations. I value both equally, even though I realize that stories make easier reading than experiments.

  Consider the related question as to whether animals say goodbye as well as hello. The latter is not hard to fathom. Greeting is a response to the appearance of a familiar individual after an absence, such as your dog jumping up at you as soon as you walk through the door. Internet videos of soldiers being saluted by pets upon return from abroad suggest a connection between the length of separation and the intensity of the greeting. We can relate to this connection since it applies to us as well. No grand cognitive theories are necessary to account for it. But what about saying goodbye?

  We dread to say farewell to someone we love. My mother cried when I moved across the Atlantic, even though we both realized that my absence would not last forever. Saying goodbye presupposes the realization of future separation, which is why it is rare in animals. But here, too, I have a story. I once trained a female chimpanzee named Kuif to bottle-feed an adopted infant of her species. Kuif acted in every way as the infant’s mother but lacked sufficient milk of her own to nurse her. We would hand her a bottle of warm milk, which she would carefully give to the baby ape. Kuif got so good at this that she’d even briefly withdraw the bottle if the baby needed to burp. This project required that Kuif and the baby, which she kept on her body day and night, be called inside for a feeding during the daytime while the rest of the colony remained outside. After a while we noticed that instead of coming in right away, Kuif would make a long detour. She’d do the rounds on the island, visiting the alpha male, the alpha female, and several good friends, giving each one a kiss, before she’d walk toward the building. If the others were asleep, she’d wake them up for her goodbyes. Again, the behavior itself was simple, yet the precise circumstances made us wonder about the underlying cognition. Like Franje, Kuif seemed to be thinking ahead.

  But what about skeptics who believe that animals are by definition trapped in the present, and only humans contemplate the future? Are they making a reasonable assumption, or are they blinkered as to what animals are capable of? And why is humanity so prone to downplay animal intelligence? We routinely deny them capacities that we take for granted in ourselves. What is behind this? In trying to find out at what mental level other species operate, the real challenge comes not just from the animals themselves but also from within us. Human attitudes, creativity, and imagination are very much part of the story. Before we ask if animals possess a certain kind of intelligence, especially one that we cherish in ourselves, we need to overcome internal resistance to even consider the possibility. Hence this book’s central question: “Are we smart enough to know how smart animals are?”

  The short answer is “Yes, but you’d never have guessed.” For most of the last century, science was overly cautious and skeptical about the intelligence of animals. Attributing intentions and emotions to animals was seen as naïve “folk” nonsense. We, the scientists, knew better! We never went in for any of this “my dog is jealous” stuff, or “my cat knows what she wants,” let alone anything more complicated, such as that animals might reflect on the past or feel one another’s pain. Students of animal behavior either didn’t care about cognition or actively opposed the whole notion. Most didn’t want to touch the topic with a ten-foot pole. Fortunately, there were exceptions—and I will make sure to dwell on those, since I love the history of my field—but the two dominant schools of thought viewed animals as either stimulus-response machines out to obtain rewards and avoid punishment or as robots genetically endowed with useful instincts. While each school fought the other and deemed it too narrow, they shared a fundamentally mechanistic outlook: there was no need to worry about the internal lives of animals, and anyone who did was anthropomorphic, romantic, or unscientific.

  Did we have to go through this bleak period? In earlier days, the thinking was noticeably more liberal. Charles Darwin wrote extensively about human and animal emotions, and many a scientist in the nineteenth century was eager to find higher intelligence in animals. It remains a mystery why these efforts were temporarily suspended, and why we voluntarily hung a millstone around the neck of biology—which is how the great evolutionist Ernst Mayr characterized the Cartesian view of animals as dumb automatons.2 But times are changing. Everyone must have noticed the avalanche of knowledge emerging over the last few decades, diffused rapidly over the Internet. Almost every week there is a new finding regarding sophisticated animal cognition, often with compelling videos to back it up. We hear that rats may regret their own decisions, that crows manufacture tools, that octopuses recognize human faces, and that special neurons allow monkeys to learn from each other’s mistakes. We speak openly about culture in animals and about their empathy and friendships. Nothing is off limits anymore, not even the rationality t
hat was once considered humanity’s trademark.

  In all this, we love to compare and contrast animal and human intelligence, taking ourselves as the touchstone. It is good to realize, though, that this is an outdated way of putting it. The comparison is not between humans and animals but between one animal species—ours—and a vast array of others. Even though most of the time I will adopt the “animal” shorthand for the latter, it is undeniable that humans are animals. We’re not comparing two separate categories of intelligence, therefore, but rather are considering variation within a single one. I look at human cognition is a variety of animal cognition. It is not even clear how special ours is relative to a cognition distributed over eight independently moving arms, each with its own neural supply, or one that enables a flying organism to catch mobile prey by picking up the echoes of its own shrieks.

  We obviously attach immense importance to abstract thought and language (a penchant that I am not about to mock while writing a book!), but in the larger scheme of things this is only one way to face the problem of survival. In sheer numbers and biomass, ants and termites may have done a better job than we have, focusing on tight coordination among colony members rather than individual thought. Each society operates like a self-organized mind, albeit one pitter-pattering around on thousands of little feet. There are many ways to process, organize, and spread information, and it is only recently that science has become open-minded enough to treat all these different methods with wonder and amazement rather than dismissal and denial.

  So, yes, we are smart enough to appreciate other species, but it has required the steady hammering of our thick skulls with hundreds of facts that were initially poo-pooed by science. How and why we became less anthropocentric and prejudiced is worth reflecting on while considering all that we have learned in the meantime. In going over these developments, I will inevitably inject my own view, which emphasizes evolutionary continuity at the expense of traditional dualisms. Dualisms between body and mind, human and animal, or reason and emotion may sound useful, but they seriously distract from the larger picture. Trained as a biologist and ethologist, I have little patience with the paralyzing skepticism of the past. I doubt that it was worth the oceans of ink that we, myself included, have spent on it.

  In writing this book, I do not seek to provide a comprehensive and systematic overview of the field of evolutionary cognition. Readers may find such reviews in other, more technical books.3 Instead, I will pick and choose from among many discoveries, species, and scientists, so as to convey the excitement of the past twenty years. My own specialty is primate behavior and cognition, an area that has greatly affected others as it has been at the forefront of discovery. Having been part of this field since the 1970s, I have known many of the players firsthand—human as well as animal—which allows me to add a personal touch. There is plenty of history to dwell on. The growth of this field has been an adventure—some would say, a roller-coaster ride—but it remains endlessly fascinating, since behavior is, as the Austrian ethologist Konrad Lorenz put it, the liveliest aspect of all that lives.

  1 MAGIC WELLS

  What we observe is not nature in itself,

  but nature exposed to our method of questioning.

  —Werner Heisenberg (1958)1

  On Becoming a Bug

  Opening his eyes, Gregor Samsa woke up inside the body of an unspecified animal. Equipped with a hard exoskeleton, the “horrible vermin” hid under the sofa, crawled up and down walls and ceilings, and loved rotten food. Poor Gregor’s transformation inconvenienced and disgusted his family to the point that his death came as a relief.

  Franz Kafka’s Metamorphosis, published in 1915, was an odd opening salvo for a less anthropocentric century. Having selected a repulsive creature for metaphorical effect, the author forced us from the very first page to imagine what it is like to be a bug. At around the same time, Jakob von Uexküll, a German biologist, drew attention to the animal point of view, calling it its Umwelt. To illustrate this new concept (German for the “surrounding world”), Uexküll took us on a stroll through various worlds. Each organism senses the environment in its own way, he said. The eyeless tick climbs onto a grass stem to await the smell of butyric acid emanating from mammalian skin. Since experiments have shown that this arachnid can go for eighteen years without food, the tick has ample time to meet a mammal, drop onto her victim, and gorge herself on warm blood. Afterward she is ready to lay her eggs and die. Can we understand the tick’s Umwelt? It seems incredibly impoverished compared to ours, but Uexküll saw its simplicity as a strength: her goal is well defined, and she encounters few distractions.

  Uexküll reviewed other examples, showing that a single environment offers hundreds of realities peculiar to each species. Umwelt is quite different from the notion of ecological niche, which concerns the habitat that an organism needs for survival. Instead, Umwelt stresses an organism’s self-centered, subjective world, which represents only a small tranche of all available worlds. According to Uexküll, the various tranches are “not comprehended and never discernible” to all the species that construct them.2 Some animals perceive ultraviolet light, for example, while others live in a world of smells or, like the star-nosed mole, feel their way around underground. Some sit on the branches of an oak, and others live underneath its bark, while a fox family digs a lair among its roots. Each perceives the same tree differently.

  Humans can try to imagine the Umwelt of other organisms. Being a highly visual species ourselves, we buy smartphone apps that turn colorful images into those seen by people without color vision. We can walk around blindfolded to simulate the Umwelt of the vision-impaired in order to augment our empathy. My most memorable experience with an alien world, however, came from raising jackdaws, small members of the crow family. Two of them flew in and out of my window on the fourth floor of a student dorm, so I could watch their exploits from above. When they were young and inexperienced, I observed them, like any good parent, with great apprehension. We think of flight as something birds do naturally, but it is actually a skill that they have to learn. Landing is the hardest part, and I was always afraid they would crash into a moving car. I began to think like a bird, mapping the environment as if looking for the perfect landing spot, judging a distant object (a branch, a balcony) with this goal in mind. Upon achieving a safe landing, my birds would give happy “caw-caw” calls, after which I would call them to come back, and the whole process would start anew. Once they became expert flyers, I enjoyed their playful tumbling in the wind as if I were flying among them. I entered my birds’ Umwelt, even through imperfectly.

  Whereas Uexküll wanted science to explore and map the Umwelten of various species, an idea that deeply inspired students of animal behavior known as ethologists, philosophers of the last century were rather pessimistic. When Thomas Nagel, in 1974, asked, “What is it like to be a bat?” he concluded that we would never know.3 We have no way of entering the subjective life of another species, he said. Nagel did not seek to know how a human would feel as a bat: he wanted to understand how a bat feels like a bat. This is indeed beyond our comprehension. The same wall between them and us was noted by the Austrian philosopher Ludwig Wittgenstein, when he famously declared, “If a lion could talk, we could not understand him.” Some scholars were offended, complaining that Wittgenstein had no idea of the subtleties of animal communication, but the crux of his aphorism was that since our own experiences are so unlike a lion’s, we would fail to understand the king of fauna even if he spoke our tongue. In fact, Wittgenstein’s reflections extended to people in strange cultures with whom we, even if we know their language, fail to “find our feet.”4 His point was our limited ability to enter the inner lives of others, whether they are foreign humans or different organisms.

  Rather than tackle this intractable problem, I will focus on the world that animals live in, and how they navigate its complexity. Even though we can’t feel what they feel, we can still try to step outside our own narrow Umwelt and ap
ply our imagination to theirs. In fact, Nagel could never have written his incisive reflections had he not heard of the echolocation of bats, which had been discovered only because scientists did try to imagine what it is like to be a bat and did in fact succeed. It is one of the triumphs of our species’ thinking outside its perceptual box.

  As a student, I listened in amazement as Sven Dijkgraaf, the head of my department at the University of Utrecht, told the story of how, at about my age, he was one of only a handful of people in the world who was able to hear the faint clicks that accompany a bat’s ultrasonic vocalizations. The professor had extraordinary hearing. It had been known for more than a century that a blinded bat can still find its way around and safely land on walls and ceilings, whereas a deafened one cannot. A bat without hearing is like a human without sight. No one fully understood how this worked, and bats’ abilities were unhelpfully attributed to a “sixth sense.” Scientists don’t believe in extrasensory perception, however, and Dijkgraaf had to come up with an alternative explanation. Since he could detect a bat’s calls, and had noticed that the rate increased when bats encountered obstacles, he suggested that the calls help them traverse their environment. But there was always a tone of regret in his voice about the lack of recognition he had received as the discoverer of echolocation.

  This honor had gone to Donald Griffin, and rightly so. Assisted by equipment that could detect sound waves above the 20 kHz range of human hearing, this American ethologist had conducted the ultimate experiments, which furthermore demonstrated that echolocation is more than just a collision warning system. Ultrasound serves to find and pursue prey, from large moths to little flies. Bats possess an astonishingly versatile hunting tool.

  No wonder Griffin became an early champion of animal cognition—a term considered an oxymoron until well into the 1980s—because what else is cognition but information processing? Cognition is the mental transformation of sensory input into knowledge about the environment and the flexible application of this knowledge. While the term cognition refers to the process of doing this, intelligence refers more to the ability to do it successfully. The bat works with plenty of sensory input, even if it remains alien to us. Its auditory cortex evaluates sounds bouncing off objects, then uses this information to calculate its distance to the target as well as the target’s movement and speed. As if this weren’t complex enough, the bat also corrects for its own flight path and distinguishes the echoes of its own vocalizations from those of nearby bats: a form of self-recognition. When insects evolved hearing in order to evade bat detection, some bats responded with “stealth” vocalizations below the hearing level of their prey.