Our organ of thought may be superior, and we may play it
better, but it is surely vain to believe that other possessors of
similar instruments leave them quite untouched.
STEPHEN WALKER
Animals have minds. They have brains, and use them, as we do: for experiencing the world, for thinking and feeling, and for solving the problems of life every creature faces. Like us, they have personalities, moods, and emotions; they laugh and they play. Some show grief and empathy and are self-aware and very likely conscious of their actions and intents.
Not so long ago, I would have hedged these statements, because the prevailing notion held that animals are more like zombies or robotic machines, capable of responding with only simple, reflexive behaviors. And indeed there are still researchers who insist that animals are moving through life like the half dead, but they’re so … 1950s. They’ve been left behind as a flood of new research from biologists, animal behaviorists, evolutionary and ecological biologists, comparative psychologists, cognitive ethologists, and neuroscientists sweeps away old ideas that block the exploration of animal minds. The question now is not “Do animals think?” It’s “How and what do they think?”
Hardly a week goes by that doesn’t see a study announcing a new discovery about animal minds: “Whales Have Accents and Regional Dialects,” “Fish Use Tools,” “Squirrels Adopt Orphans,” “Honeybees Make Plans,” “Sheep Don’t Forget a Face,” “Rats Feel Each Other’s Pain,” “Elephants See Themselves in Mirrors,” “Crows Able to Invent Tools,” and (for me, as a dog lover, a favorite) “Dog Has Vocabulary of 1,022 Words.”
How do scientists know that a dog has such an impressive vocabulary, that moths remember they were once caterpillars, that blue jays regard other jays as thieves, or that not only whales but cows, too, have regional accents? How can we prove that animals think? Once we have done so, what does that tell us about our relationships with them, and what does it tell us about ourselves?
Many of us have had some experience—playing with a pet or watching wildlife—that made us think an animal was planning something, or feeling joyful or sad. My husband and I are sure that our dog smiles, especially when he’s playing with us, or when we give him a promised bone, or when we all are reunited after one of our business trips. We laugh with delight to see his joy and say things like “Look at how happy Buck is. He’s really excited about getting his treat.” But is he? Without language, is there any way to rule out what else he might be thinking about? Maybe he just caught a whiff of a squirrel’s scent, or some of our old socks, or maybe he’s not smiling at all but simply doing his best to imitate an expression he often sees on our faces and perhaps associates with bones or walks but doesn’t fathom in the slightest.
Although, like many pet owners, I’ve often had the gut feeling that my dog and cats have mental and emotional lives, I’ve never tried to prove this—I’m a science writer, not a scientist. The only “proof” I can offer is that my pets’ behaviors, activities, and facial expressions all suggest thoughts and emotions. Isn’t that one reason, perhaps the main reason, we have pets in our homes? We want the company of lively, expressive creatures, beings that can be fun and loving, grumpy and bored, and that relate to and respond to us as only another living being can. In short, we want to be around something more than pet rocks.
I don’t think I’ve ever met a pet owner who didn’t have a story about his or her smart dog or clever cat. Probably we like having smart pets because, like smart people, they’re interesting and entertaining. And sometimes our smart pets make us think.
In many ways, it was because of our first very smart dog, Quincie, a mixed-breed collie, that I began thinking about writing this book. When she was a puppy, Quincie liked to carry a pine cone in her mouth on our daily mountain hikes. I don’t know why she enjoyed this, but at the trailhead she always searched among the cones and picked out one to take with her. One day, as we hiked up a steep path, she suddenly stopped, set her cone down, and nudged it over the side of the trail with her nose. She watched intently as the pine cone tumbled down the slope, and when it reached a certain momentum raced after it as if she were chasing a rabbit. She had imagined a game, invented it, and she played it almost every time we hiked that trail.
“She has an imagination!” I remember saying to my husband the first time Quincie did this. I was surprised, even though, of course, she also played imaginary games with us, as most dogs do, barking and pretending to be a “mean” dog when we chased her—though all the while she was also wagging her tail and giving us other signs that this was just for fun. My cats, too, delight in chasing balls, fabric mice, feathers or bits of cardboard on a string—all of which they are able to imagine as living prey. But it’s not just the movement of the toy they enjoy. What they really seem to want is for me to play the game with them; and they have their methods—a certain cry and way of looking at me—to let me know this is what we should be doing.
So why was I surprised when our pup invented a game? I think because at that time, in the late 1980s—not so very long ago—scientists were still stuck on the question “Do animals have minds?” A cautious search was under way for the answer, and the researchers’ caution had spilled over to society at large. In those days, if you suggested that dogs had imaginations or that rats laughed or had some degree of empathy for another’s pain, certain other people (and not just scientists) were likely to sneer at you and accuse you of being sentimental and of anthropomorphizing—interpreting an animal’s behavior as if the creature were a human dressed up in furs or feathers. My story about Quincie remained that: a story, an anecdote I shared only with close, dog-loving friends. Although I puzzled over Quincie’s inventiveness, I didn’t know how to interpret her pine cone game or whether to discuss it with the scientists I often interviewed about animals and animal behavior.
Shortly before watching Quincie invent her game, I had another thinking-animal experience—this time with a wild animal, an orphaned chimpanzee, and I was in the company of Jane Goodall, the world’s most famous ethologist, a scientist who studies animals as they go about their lives in the natural world.
I had traveled to Goodall’s study site in Tanzania, Gombe Stream National Park, to interview her for a biography I was writing about her mentor, Louis Leakey, the renowned fossil hunter who had helped launch her study. While at Gombe I hoped to have some time to watch the chimpanzees, and Goodall thought I should as well. She suggested that I join one of her lead researchers, David Gilagiza, a slender Tanzanian who was then collecting data on mother-and-infant relationships. He would be concentrating on Fifi, a much-revered female in the so-called F-family, and her toddler, Fanni, and infant, Flossi.
Nothing—not the books and articles I had read, or the TV specials I’d watched—had prepared me for my first encounter with wild chimpanzees. Gilagiza and I left the park’s guesthouse shortly after dawn and hiked up a narrow trail that led away from the misty shores of Lake Tanganyika and into the woods that sheltered the chimpanzees. It was cool and quiet beneath the forest canopy, and we walked at a steady pace, with Gilagiza stopping now and then to point out plants of interest or places the chimpanzees favored.
The Gombe forest seemed like paradise. Blue butterflies the size of my hand fluttered among the flowers and ferns lining the path, while a tinkling stream sparkled below the trail. I was just about to ask Gilagiza where in these happy woods we would find Fifi when two dark, furry shapes—chimpanzees!—suddenly raced past us. The second one paused just long enough to slap my legs. “That was Frodo, Fifi’s son,” Gilagiza said, a worried look on his face. “You must watch out for him!”
Frodo, then in his late teens, would eventually become Gombe’s dominant male. But when I met him, he was simply an ambitious and frustrated adolescent working his way up the chimpanzee social ladder. Frodo wasn’t the smartest or most diplomatic of chimpanzees, but he was strong, and as part of his climb to power he had already beaten up most of the females. Lately he’d begun testing his prowess against human females. He had attacked some of the women researchers—even Goodall—and I should do my best to stay out of his way, Gilagiza said. I nodded, although I wasn’t sure how to keep an eye out for this particular chimpanzee. I’d barely caught a glimpse of him and didn’t know what I should do if I encountered him again. I also wondered if he would remember me. And if he did, would he try again to impress the other males by hitting me? Were chimpanzees capable of that kind of plotting and planning?
I fell in behind Gilagiza and stayed close—as female chimps often do, joining males that may protect them from other male attackers.
Frodo was my first encounter with a wild chimpanzee, and I wasn’t sure what to make of what had happened—or of him. Despite all that I’d read, I had not expected to so quickly meet a thinking chimpanzee. To see that type of behavior, I thought, required weeks and months, even years, of careful watching and note taking. Frodo’s slap opened up a host of questions for which I had no answers. Over the next few days, my questions only grew as we spent time watching the chimpanzees, most of whom seemed to ignore us. But that didn’t mean that we were like rocks or bushes to them.
Once Gilagiza and I sat near two chimps who were busily stripping the leaves from long, skinny twigs—making tools. When they’d readied these instruments, the chimps took turns dipping them into a small crevice in the earthy mound of a termites’ nest and deftly extracting the insects—which they then nibbled as we would peanuts or potato chips. Goodall’s studies had shown that this termite fishing requires experience, dexterity, and skill. Why didn’t the chimpanzees merely spend their days collecting easy-to-gather fruits? That would be the sensible, machinelike response for any animal hunting food in the wild. I’d rarely thought about how food might taste to wild animals, yet here were two chimpanzees smacking their lips with delight. Could it be that they bothered to fish for termites because they enjoyed this snack? Why wouldn’t animals seek out pleasure and fun, just as we do?
On another morning, we watched from a greater distance as two male chimpanzees (neither of them Frodo) brawled through the woods, screaming and slapping at each other. They puffed up their hair to supersize their bodies and uprooted small trees that they shook at each other like spears. I wasn’t sure who won or lost this match, but at the end, their wrath spent, one held out his hand to the other—a gesture so easily understood that Gilagiza didn’t bother to explain. The two chimps briefly touched, while whimpering, and went their separate ways. Gilagiza didn’t know what they had been fighting about, but at the end they patched up their quarrel, just as we do when we know it’s better to remain friends with someone than to have an enemy.
We also spent time every day with Fifi’s family, usually in picniclike settings under shady fig trees. To my dismay, Frodo, who was Fifi’s eldest son, was often with them, but he never looked my way. Had he forgotten our first encounter, or was there no need to put on a show in his family’s presence? Whatever the reason, he seemed an entirely different chimpanzee. He feasted quietly with his mother on the sweet fruits or sat with his back to her so she could groom him, while the young Flossi, pink-faced and bright-eyed, swung and tumbled among the vines, as playful as any toddler. We spied on Fifi’s family at dusk, too, as they gathered in the treetops and bent the twigs and boughs into leafy beds for the night, then snuggled in together—yet another scene that needed no translating.
Although wonderful to watch, none of these were surprising chimpanzee behaviors. Goodall had thoroughly documented and reported them all. What I didn’t expect to witness—just as I hadn’t anticipated Frodo’s decision to involve me in his social ambitions—was one chimpanzee deceiving another.
Goodall had gone to the “station,” a small shed at Gombe, where she had long provided bananas to the chimpanzees to accustom (or habituate) them to people. She handed the fruit to the chimps through a barred window. One afternoon, I watched the proceedings from an adjacent building.
Beethoven, a big male with glossy black fur, was the first visitor. With him was a young female chimpanzee, Dilly, whose mother had disappeared when Dilly was a toddler, leaving her an orphan. As a rule, chimpanzees are raised by their mother, and any orphaned youngsters are cared for by one of their sisters or aunts. But in this case, it was the male, Beethoven, who’d adopted Dilly, Goodall told me later.* Beethoven was both Dilly’s benefactor, seeing to it that she had enough to eat from the fruiting trees, and her protector, keeping her safe during any of the group’s altercations. But Beethoven’s generosity did not extend to sharing bananas.
Goodall handed Beethoven an armful of the fruits, and he squatted on the grasses in front of the shed and with relish devoured each one. Little Dilly sat close by, watching as each luscious banana slipped down her protector’s gullet. Once she reached out a hand to beg, but Beethoven ignored her. Finally, the last banana consumed and his belly full, Beethoven rolled on his back and fell asleep. Dilly sat beside him, grooming his fur.
Goodall had watched the little drama from her window. Unbeknownst to Beethoven, she had held back one banana. When Dilly happened to glance at her, Goodall held up the prized fruit. Normally, a hungry chimpanzee would make a food cry after spotting such a delectable treat. Dilly stifled any sound. She watched as Goodall placed the banana outside the feeding station, away from Beethoven’s line of sight. It was as if she and Goodall had exchanged a secret, and like a coconspirator Dilly played her part. She continued grooming the big male, while making cooing, lullaby sounds of contentment.
At last Beethoven began to snore—and Dilly quickly and quietly made her way to the hidden banana. She downed it in three bites. Then she stealthily made her way back to Beethoven’s side and resumed her grooming and cooing.
When Goodall and I met up a bit later, I immediately brought up Dilly’s behavior.
“What a wonderful demonstration of how chimpanzees can lie and be deceitful!” I said. “Are you going to write that up for a science journal?”
“I can’t,” Goodall replied.
“But why not?” I asked. Dilly’s actions had been so clearly deceptive; she had even connived with Goodall to fool Beethoven. How else could one explain that sequence of events?
Goodall said calmly, “No. Other scientists will say this is only an anecdote and that there is no way to know what Dilly was thinking. If I write it up, everyone will say, ‘Oh, Jane, how silly of you. That’s anthropomorphizing.’ ”
She would be attributing a human mental ability to an animal—just as I had done when I told friends about my dog’s imagination. But there was a big difference: she was Jane Goodall, an eminent scientist and expert on chimpanzee behavior. If she reported Dilly’s deception, I protested, surely other researchers would listen. Goodall and other chimpanzee watchers, such as Frans de Waal, who had written extensively about the chimpanzees’ political machinations, had already established that these apes shared many of the attributes and abilities of humans. The chimpanzees were so similar to us, especially in their expressions and gestures, that at the end of each day, after returning to the guesthouse, I often referred to them as “people” when telling other tourists all that I’d seen.
Goodall nodded. “Yes, it doesn’t make much sense to say they aren’t thinking or don’t have emotions,” she said. “Most of us studying animals in the wild see things like this [Dilly’s deception] all the time. But we’ve learned to be careful. We can say, ‘If Dilly were a human, we would say she was acting deceitfully.’ ” To say that Dilly—or any animal—had what we would call subjective or personal experiences would be considered unscientific. Although some animals might have an inner, mental life, we had no way of asking them about it and so could not study it.
I asked Goodall how scientists could possibly get around this dilemma. The rules of the game seemed stacked in such a way as to forever preclude knowing what was in the mind of another creature. Goodall agreed but added that because so many researchers were witnessing similar behaviors (and in a variety of species, not just chimpanzees), she thought the science—the study of animal cognition and emotions—would change. “It has to,” she said. “It’s just a matter of time.”
As I listened to Goodall, I realized how little I knew about animal cognition, how scientists define it or study it. Why didn’t scientists think it possible to study the thoughts and emotions of animals, particularly one as closely related to us as a chimpanzee? Weren’t the chimpanzees (not to mention the baboons that lingered near the guesthouse) thinking? And if they weren’t thinking, what were they doing? One look at the baboons, which sometimes hung on the guesthouse’s grated windows while surveying my provisions, and I knew what was on their minds: They were waiting for me to make a mistake—to leave a window or the door unlatched—so they could dash inside and steal my food. Simple, common sense, and the baboons’ crafty, calculating eyes told me as much. Why did scientists struggle to explain—or simply deny—what seemed so obvious to me?
In fact, we have been wrestling with the question of what goes on inside the minds of animals at least since the time of the Greek philosophers, and surely long before that.†
ARISTOTLE DOUBTED that animals could think rationally, although he did allow that they certainly had appetites and were capable of experiencing sensations, such as hunger, pain, and anger. Stoic philosophers, such as Zeno, had a far narrower view. They discounted the possibility that any animal had thoughts or emotions or sensations and argued that there was no reason to extend any moral considerations to them. Early Christian thinkers, notably St. Augustine, embraced the Stoics’ position, and their philosophy has dominated Western ideas about animals ever since.
Most of us are familiar with the Stoics’ attitudes because they influenced the seventeenth-century philosopher Réné Descartes. He is most famous for his dualist philosophy, which considered the mind and body as two separate entities—the material body and the immaterial mind or soul. The immaterial part, Descartes argued, linked humans to the mind of God. (It’s largely thanks to this Descartian division that many of us in the West don’t think of our thoughts or minds as anchored in the physical brain. Instead, we picture them—and cartoonists and illustrators typically draw them this way—as floating outside and above our heads, often in fluffy “thought bubbles,” coasting heavenward.)
In Descartes’s philosophy, since animals are composed only of material substances, they are necessarily lesser beings. They lack both minds and souls, have no capacity for reason, and are not connected to the mind of God. Instead, Descartes regarded animals as complex automatons, clockworklike things that can see, hear, and touch but are not conscious. Reasoning required language, Descartes argued, and animal calls were only automatic sounds made in response to external stimuli. One of his followers, the philosopher Nicolas Malebranche, summarized the Descartian view: “[Animals] eat without pleasure, cry without pain, grow without knowing it; they desire nothing, fear nothing, know nothing.”
Other philosophers vehemently disagreed with such statements. All one need do, Voltaire practically shouted at Descartes’s followers, was to witness one of the vivisectionists dissecting a dog alive (as was done all too often in the seventeenth and eighteenth centuries, to judge from the numerous accounts of this cruel practice). “You discover in him all the same organs of feeling as in yourself,” Voltaire exclaimed in 1764. “Answer me, mechanist, has Nature arranged all the springs of feeling in this animal to the end that he might not feel?”
At the time, there was no ready way to settle the matter. On one side were philosophers and theologians who saw humans as the product of a special creation and therefore completely separate from animals. On the other were thinkers who argued that there were sufficient similarities between people and animals that we should be kind and compassionate toward our mute brethren.
In 1859 in On the Origin of Species, Charles Darwin presented a solution to this impasse. Animals were not machines or automatons, he argued, but biological organisms that had evolved (and were evolving) in response to natural pressures and changing conditions on Earth. By animals, he meant humans, too. Lumping humans with all other animals was a shocking statement because it meant that we were not specially created. We shared anatomical, physiological, and psychological similarities with animals because, Darwin explained, we were descended from other animals. (Although Darwin did not have genetics at hand to prove his case, we now know that humans and chimpanzees share 98 percent of their genes; humans and fruit flies share 44 percent of their genes.)‡
Darwin realized that his discovery of the rules that govern the evolution of life would lead to new understandings in many sciences, including psychology. In Origin, he did not discuss in detail how evolution shaped the mental lives of animals, but he foresaw that in the future “psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.” In other words, just as the physical human body had an animal past, so did the human brain and mind. Darwin was convinced this was the case because while writing Origin he had collected many observations—some his own, some supplied to him by colleagues—documenting the mental and emotional similarities of humans and animals. He explored both aspects in his next two works, The Descent of Man (1871) and The Expression of the Emotions in Man and Animals (1872)—books that would help usher in two new fields of science in the twentieth century: ethology, the study of animals in their natural settings, and comparative psychology. (In fact, rereading Darwin for this book, I was struck by how forward thinking he was; his writings could easily serve today as textbooks in cognitive ethology and comparative psychology classes, or as primers for anyone interested in the subjects.)
In The Descent of Man, Darwin argued that animals and humans differ in their mental powers only in degree, not in kind—meaning that animals share some of our abilities for reason, memory, and language and also possess an aesthetic sense. Our cognition is more complex than that of other animals, but that complexity is the only difference. All animals, including humans, face the same challenges of life, he observed. They need to find food, mates, and their way around their world, while avoiding predators and hazards—all tasks requiring problem solving and categorizing abilities. Animals use their senses to acquire knowledge about the world, just as humans do, and they act on that knowledge, which gives them a measure of intelligence. Even earthworms, Darwin would argue in a later book, are cognitive beings because, on the basis of his close observations, they have to make judgments about the kinds of leaves they select to plug their burrows. He hadn’t expected to find thinking invertebrates and remarked that the hint of intelligence in earthworms “has surprised me more than anything else in regard to worms.”
Darwin also placed our human emotions and our manner of expressing them in an evolutionary context. Facial expressions and body postures, he explained, are the signals we and a host of species use to communicate such emotions as joy, fear, affection, and anger. Animals, whether birds, monkeys, apes, or humans, are so strikingly similar in the signals they use to convey an emotion (for instance, when angry, swans puff up their feathers; chimpanzees erect their body hair; we enlarge our chests; we may snarl like a dog, too) that Darwin argued there are “general principles” of expression. Indeed, these emotional signals, including displays of pain, are so useful for social communication that they have become innate instincts, he said—and, thus, are subject to the same forces of natural selection that shape the anatomy of all animals, including humans.
Darwin readily attributed emotions to many species, including lizards, birds, cats, dogs, horses, monkeys, and apes, and wrote of them as beings with rich and complex mental lives. In his writings, animals have motives, intentions, and desires; they do not “seem” to do things—they do things. “Though led by instinct,” he wrote about male birds’ mating competitions, “they know what they are about, and consciously exert their mental and bodily powers” to try to win the female.
Darwin’s protégé George John Romanes, an English evolutionary biologist, took Darwin’s study of animal minds a step further. The two were close friends, and Darwin gave the younger man his forty-year collection of notes and papers on animal intelligence. Using these materials and other studies, Romanes compiled a nearly five-hundred-page volume on the subject. Titled simply Animal Intelligence, his 1886 book attempted to present all that was then known about the “mind in animals.” At the outset, he acknowledged that “we can only infer the existence and nature of thoughts” in other organisms on the basis of their behaviors. Nevertheless, Romanes argued that because animals could learn, they must have minds—the same argument that was used at the time to explain the existence of minds in humans.
Following Darwin, Romanes argued that scientists could study the mental states of animals by using a kind of “inverted anthropomorphism”—that is, turning to our human emotions and mental abilities as guides. When we see a dog or monkey (or even a bee) acting in an affectionate or jealous manner, it’s likely the animal is experiencing the emotion much as we do (although given its evolutionary distance from us, he noted, much less so in the case of the bee). Romanes then set about examining such topics as the instinctive behaviors of protozoa, memory and sympathy in ants, pugnacity in termites, and jealousy in baboons.
Romanes’s book was a hit with the general public but not among other researchers who worried that Romanes and Darwin had both relied too heavily on anecdotes for their evidence and not sufficiently on replicable experiments. Most damningly, Romanes’s critics claimed he had done little more in his book than describe animals as fur-clad humans. Although this was not an entirely fair assessment, it continues to be the way that Romanes’s work is most often portrayed, ensuring that it is seldom read or that it serves only as a cautionary lesson of how not to do science.
Romanes’s writings, even more than those of Darwin, triggered a debate about how scientists should study animal minds. Some thought Darwin’s and Romanes’s “anecdotal” method had merit if the anecdotes were collected carefully and critically. Others thought a more objective approach was needed; they didn’t deny that animals had subjective, mental experiences but claimed that these couldn’t be studied because they weren’t physically observable and couldn’t be measured.
In the early twentieth century, one group of psychologists went even further and refused to accept that conscious activity played a role in any animal’s behavior, including that of humans. These scientists called their field “behaviorism,” since they restricted their studies to animals’ observable behaviors. In their approach, unobservable events—such as desires, memories, ideas, beliefs, emotions, thoughts—were off the study table, both for humans and for animals. “The real question is not whether machines think, but whether men do,” B. F. Skinner, probably the most famous of all behaviorists, once said in a sweeping dismissal of mental experience. And if humans do not think but only react to stimuli, why even bother to ask if animals think or feel?
Strict behaviorism, as the science came to be called, had about the same effect on animals as Descartes’s philosophy. Once again, animals lost their minds—and any capacity for reason or emotion. Many animal rights observers have noted that it wasn’t a coincidence that the use of animals in biomedical studies and pharmacological testing, and as industrially raised and hunted meat and fur products, grew exponentially while behaviorism flourished. Behaviorism dominated both human and animal psychology in the United States for much of the twentieth century and still has a number of influential adherents in animal cognition research.
Early ethologists were also extremely cautious about the question of animal minds. Niko Tinbergen, the pioneering Dutch ethologist, ruled out attributing mental desires or motivations to what animals do or how they behave. Tinbergen, along with the ethologist Konrad Lorenz and honeybee researcher Karl von Frisch, showed that instinct (meaning innate responses) and imprinting, an instantaneous type of learning, could explain some of the complex behaviors of birds and bees. Their approach had more influence in Europe and England than in America, but the result was the same: for most of the twentieth century, animal minds were off limits for serious scientists, whether studying animals in the wild or in the lab.
Which brings us back to Jane Goodall. She wasn’t university educated and had never studied psychology or ethology when she began watching the chimpanzees in 1960. Goodall’s mentor, Louis Leakey, thought her lack of training a good thing, since she wouldn’t bring preconceived ideas to what she was observing. Unaware that chimpanzees were mindless, she wrote about them in ways that were scientifically forbidden, using words such as motivation, excitement, and mood in her depictions of the apes’ behaviors. She described the chimpanzees as having “personalities,” gave them “childhoods,” and when referring to individual chimps used the personal pronouns he and she instead of the supposedly objective it. (Her editor at the prominent British science journal Nature replaced the personal pronouns with it on her first manuscript. She replied by crossing out the “its” and restoring the pronouns, later saying that the final version had at least “conferred on the chimpanzees the dignity of their separate sexes.”) Her vocabulary cost her dearly at first, because scientists believed such words made the chimpanzees seem like humans and clouded our understanding of their behaviors. Sharply criticized for anthropomorphizing, she was shunned for many years at scientific conferences, and her writings were regarded with suspicion.
But that was years before I met Goodall at Gombe. By then, in 1987, she had won over most of her critics, which made her comments to me about how she could not come right out and say that Dilly had deceived Beethoven all the more surprising. The previous year she had published her great work The Chimpanzees of Gombe: Patterns of Behavior, documenting the individual life stories of forty-one of the chimps she had watched for twenty-five years. It was the chimpanzee equivalent of a long-term sociological study of a human community. When you finish her book, you realize why, if you want to understand chimpanzee behavior, you need to know about their gender, childhood, and personalities. Just as with humans, these factors influence how individual chimpanzees make their decisions and relate to their family and community. While Goodall relied heavily on what some might call anecdotes, hers were carefully collected, rich with detail, and substantiated where possible with statistics. She had not spoken to a single chimpanzee, yet she showed us chimpanzees in love, at war, parenting, inventing cultures, and playing politics.
Goodall had said to me that the field would change—and she was right. Her book and studies (as well as those of such prominent ethologists as George Schaller, Frans de Waal, Cynthia Moss, Marc Bekoff, Barbara Smuts, Gordon Burghardt, Louis Herman, and others) helped pave the way for other scientists interested in understanding more about animals than strict behaviorism would allow. By 1987, behaviorism in fact was beginning to wane. As applied to humans, it had started slowly going out of fashion in the 1950s and 1960s when the cognitive revolution, which explains thought and emotion in terms of universal mental mechanisms, swept through human psychology departments. The scientists behind the revolution found it absurd to claim, as the behaviorists did, that human mental experiences cannot be studied because you can’t observe them. Physicists also study things that can’t be directly observed, noted Bernard Rollin, a philosopher and animal scientist. “[They] talk of all sorts of entities and processes, from gravitation to black holes, which are not directly verifiable or directly tied to experiments,” but these “theoretical notions” have not held back their field. In fact, their unobservable ideas “help us to understand the physical world far better than we would without them.”
Under behaviorism, everything we humans (and other animals) do was regarded as entirely the result of a stimulus and a response—a dinner bell rang, and you (and the dog) drooled. But as Steven Pinker makes clear in How the Mind Works, we know that our beliefs and desires influence our behavior. For example, Pinker says all we have to do is imagine a man who boards a bus because he wants to visit his grandmother and because he knows the bus will take him to her home. The wanting and knowing are beliefs—mental elements that are weightless, odorless, colorless, tasteless, invisible. Yet the man boards the bus because of them. Although invisible, they cause his concrete, observable actions—but how? The computational theory of mind, which was the key breakthrough of the cognitive revolution, solves the puzzle by picturing the brain as a device for taking in information and processing it. The theory also explains that—and this, as Pinker says, is its brilliance—beliefs and desires are information. We don’t yet know how this type of information is physically encoded in our brains’ neurons, but it is there both causing and affecting our actions and decisions.
So why not apply the discoveries of the cognitive revolution to animal minds, too? Donald Griffin, an animal physiologist who discovered that bats find their way and hunt prey via echolocation, decided in 1976 that it was high time to do so. There was such a “ferment of constructive excitement in ethology,” he wrote in The Question of Animal Awareness, coupled with the new understandings of how human minds work, that biologists needed to renew the investigation into the “possibility that mental experiences occur in animals and have important effects on their behavior.” Griffin had been puzzling about the minds of animals since attending a science symposium in 1948, where von Frisch discussed his experiments with honeybees. “Good God, if mere insects communicate abstract information about distance and direction,” Griffin wrote about the moment that “shook up” his thinking about animal cognition, “ … how could I be so sure that homing birds simply search for familiar landmarks? … Although I still considered myself primarily a physiologist and directed my efforts toward mechanistic explanations of animal behavior, I came to see that those mechanisms must be much more subtle and versatile than I had imagined.”
Some scientists recoiled from Griffin’s book as if Romanes had been reborn. But not so the younger generation, who jumped at Griffin’s challenge to find ways via both experiments and field studies to investigate and document animal minds—including the possibility that they might be, as Griffin suggested, self-aware and conscious. Griffin called his new approach “cognitive ethology.”
For a field of science to succeed, researchers need a coherent framework—an overarching theory—to guide their questions. Griffin provided that, urging his readers to turn to Darwin and seek an understanding of animal minds through the “evolutionary continuity of mental experience.” Without evolution as a guide, the cognitive skills of people do not make sense biologically. What, after all, are the biological roots and history of our cognition? How have evolutionary processes shaped the ability to think and experience emotions? What are the mental experiences of other animals? In short, how and what do animals think?
Griffin, with Darwin in hand, opened a door to these once-forbidden questions, and by the end of the twentieth century, scientists were rushing through.
AFTER WATCHING DILLY’S DECEPTION at Gombe, I’d left with many questions about what we know and don’t know about animal minds. I added more questions as the magazines I most often write for, Science and National Geographic, sent me on assignments to join ethologists and biologists studying a wildlife lover’s dream list of animals: elephants, lions and cheetahs, humpback whales, Ethiopian wolves, pink river dolphins, gelada baboons, howler monkeys, golden marmosets, poison dart frogs, and a good half-dozen species of bowerbirds. Each journey was like a crash course in animal behavior—in learning how to watch and think as the scientists do, with an open mind, patience, and an alertness to details.
The elephant watchers I joined in Kenya, for instance, recorded every ear flap of an elephant matriarch and her kin; those subtle movements held the clues to the decisions the elephants were making and wordlessly told the other elephants how they were feeling and what they were about to do.
And in Australia, scientists studying the greater bowerbirds mapped and tabulated the thousands of stones, glass shards, and other decorative bits the male birds use to ornament their bowers—which are like theatrical stages where the males sing and dance to attract females. I felt a surge of pity for the scientist as she knelt next to one bower and showed me the code she’d written on each little stone and piece of glass—there were hundreds, if not thousands, of these, and this was only one bower. Yet the dull, time-consuming work led to the discovery that the bowerbirds aren’t just randomly setting out their piles of decorations but arranging them to create the illusion of perspective, a technique often used by artists when painting landscapes. For their illusions, the birds place the largest ornaments farthest away from the opening of their twiggy corridors and the smallest ones closest to it. Thus a female bowerbird standing inside the corridor and looking out would perceive all the items to be about the same size. The researchers proved that the males intentionally create this illusion by rearranging the birds’ displays. The birds quickly restored every item to its proper place. Bowerbirds, the scientists concluded, are artists—the first animal, other than humans, that is fully recognized as having an artistic sense.
Over the years, I noticed that many scientists were increasingly at ease talking about the likely mental states and experiences of the animals they were watching—just as Goodall had predicted. Some scientists, such as elephant researcher Joyce Poole, evidenced an almost complete indifference about anthropomorphizing or earlier ideas that denied animals their minds. As we drove through Kenya’s Amboseli National Park, Poole addressed the elephants that came up to her Land Rover’s window as old friends. When they reached their trunks inside the car to sniff her, she laughed, “Yes, it really is me. And, yes, I know. I’ve been gone a long time.” From her time among the elephants, she knew (and had the data to show) that they had long-term memories and recalled individual elephant friends. They remembered humans, too, distinguishing between those who had never harmed them and those who had heaved spears their way.
In Tanzania’s Serengeti National Park, ethologist Sultana Bashir spoke with sorrow about what fate surely lay in store for a male cheetah we were watching. Several months prior to my visit, she and other members of the Serengeti Cheetah Project had placed a radio collar on this sleek cat. We’d driven long hours over the plains, while tracking the collar’s ping, before Bashir spotted the cheetah among the grasses. He was standing at the base of a rocky kopje—his lookout—and crying in a piteous tone. Sometimes he climbed his rocks to gaze into the distance, other times he paced away, then suddenly swung about and climbed back to the top of his lookout. “Mrrrroow; mrroowww; mrroww,” he called, making a low bleating sound, almost like the cry of a wounded sheep. “That’s his distress call,” Bashir said. “He’s looking for his friend. But I’m afraid he’s gone; he was elderly, and I think he’s died. Otherwise, he would be here, or nearby.”
Male cheetahs maintain large territories that overlap those of several females, and they fight other males—sometimes to the death—to secure their borders. In such battles, it helps to have a friend; indeed, a single male cheetah without a partner is almost assured of losing any fight and all his territory. We sat with the unhappy male until late in the afternoon, and he never ceased his cries. At last, he left the kopje behind and headed off at a trot into the plain’s tall grasses. What would become of him if his friend did not return? I asked. “He’ll go off to die, I think,” Bashir said. “Another male will kill him, or he’ll stop eating, get mange—always a sign of stress in cheetahs—and become too weak to defend his territory. Really, he’ll die of a broken heart.”
I didn’t ask Bashir or Poole for evidence to back up their statements. I simply jotted down their words, because the experiences were affecting and because the scientists didn’t talk in jargon but spoke openly and simply about what was happening: an elephant had come to visit an old friend; a cheetah was dying from a broken heart.§
In 2006 National Geographic asked me to write an article about how animals think. The resulting cover story, Minds of Their Own, was published in the March 2008 issue and became the genesis for this book. Reporting took me around the world—from my home in Oregon to several states as well as to Japan, Venezuela, Costa Rica, Australia, Germany, England, Hungary, Austria, and Kenya—to meet researchers and their animals. At each lab or field site, I watched raptly as scientists unveiled some aspect of the minds of insects, parrots, crows, blue jays, fish, rats, elephants, dolphins, chimpanzees, wolves, and dogs—and what the animals were thinking.
IT’S PROBABLY BEST at this point to explain what I mean by thinking. First, it is an activity that takes place in a physical place, the brain. And second, to borrow from Richard Dawkins and Steven Pinker, the ultimate goal of thinking is to help ensure that the individual with the brain successfully reproduces, thereby making as many copies of the genes that created that brain as possible. What does an animal need to do in order to replicate? It needs to eat, so it must be able to find food. It needs some type of territory or home, so it must be able to find its way through the forest, waters, deserts, or skies, while avoiding hazards. Often an animal will have to elude predators, defend its home turf, or compete with others for a mate. And many animals must raise their young after they are hatched or born.
Animals must learn how to do many of these tasks, and this learning requires them to have memories and the ability to respond to new experiences and new information. The main purpose of learning and memories, and of cognition overall, is to reduce the uncertainties of life and to help an animal predict what may happen in the future.
Thinking in its simplest form may be something like information processing, as scientists such as Alan Turing, one of the key thinkers in the cognitive revolution, suggested in 1950. A brain takes in information via the senses—eyes, tongue, ears, skin, feather, scales, electrically sensitive whiskers, and so on—processes it, and produces a decision in the form of an action or behavior. The action, of course, leads to more information and to another behavior, so that a loop is created between senses, thoughts, and behaviors. Or, as a pair of biologists wrote, thinking “tempers the raw sensory information and prepares new electrical signals to further influence thought and behavior.”
Often simple cognition is compared to the set of instructions that directs a computer as it processes data. Of course, that is only a metaphor for how a mind works. In most organisms, the instruction set is much more complicated. Learning, memory, hormones, emotions, gender, age, personality, and social factors—all the messiness of biology—come into play, too.
In human psychology, there’s no longer a question about whether cognition operates separately from the emotions. It doesn’t. There aren’t separate pathways in the brain for thinking and for emotional feelings; they work together on a single track. The same is probably true for all vertebrates, possibly even some invertebrates—even though animals’ emotional states are seldom studied. We know less about the emotional side of animal cognition than any other aspect. Comparative psychologists and cognitive ethologists don’t deny that animals have emotions, but, as Frans de Waal has pointed out, they have not discovered how to study them.
Many researchers shy from the problem of animal emotions because they worry that such “inner states” cannot be studied—basically, the same argument behaviorists once used as the reason not to study cognition. I’ve also heard it argued that animal emotions are likely very simple and/or vastly different, even “alien,” from those of humans (as if species other than us came from another planet). There is simply no evidence to back up such statements. Because evolution is conservative (for instance, human brains and those of all vertebrates, including fish and amphibians, use the same set of chemicals to transmit signals), it’s more likely that many of our emotions are similar to those of other animals, as de Waal notes. Why, after all, reinvent sensations, such as fear, pain, or love, and the internal states or mental representations that accompany these? Emotions most likely help animals to survive and reproduce.
When I use the term thinking, I’m not implying that animals have language, because thinking does not require language. Thoughts can come as vivid mental images. For instance, the poetry of Samuel Taylor Coleridge often appeared to him in a visual way, and Albert Einstein wrote that his insights typically came as a result of picturing himself doing something like riding a beam of light. Scientists don’t know how thoughts are represented in the minds of animals, but some speculate that other animals also think graphically, perhaps in pictures, possibly even animation.
Thinking may or may not require being conscious, depending on how consciousness is defined; it’s a term that scientists have yet to agree on. In the past, only philosophers studied consciousness. But in recent years, neuroscientists and evolutionary biologists have entered this debate, arguing that because the mind is based in biology, consciousness must be as well—and it must have evolved. “Consciousness does not belong only to humans; it belongs to probably all forms of life that have a nervous system,” the distinguished neuroscientist Rodolfo Llinas commented in a 2001 interview for NOVA. He explained, “This is basically what consciousness is about—putting all this relevant stuff there is outside one’s head inside, making an image with it, and deciding what to do.” Scientists do not yet know how consciousness emerges from the neurons and organization of the brain, but they are making good progress, gaining insights both from neurological patients who have suffered some type of altered consciousness and from monkeys and rats whose brains are scanned while they are making decisions. Several leading cognitive neuroscientists and neuroanatomists are now so confident about the biological basis of consciousness and the idea that other animals are conscious that they wrote a declaration on the subject at a University of Cambridge conference in 2012. It declares, in part, that “humans are not unique in possessing the neurological substrates that generate consciousness. Nonhuman animals, including all mammals and birds, and many other creatures, including octopuses also possess” these—and therefore, they must be conscious. Other mental abilities may be linked to consciousness—such as self-awareness, empathy, insight, and something called “theory of mind,” which is the ability to attribute mental beliefs, desires, and intentions to both oneself and others. These, too, must be “evolved, emergent qualities of brains,” as the evolutionary biologist Richard Dawkins has described consciousness. And, as such, it is most likely that there are degrees of each one of these abilities in various species throughout the animal kingdom, with the most advanced found in species possessing complex nervous systems and the biology for consciousness.
THERE IS ONE MORE POINT to be made about animal minds and evolution. Evolution is not a progressive force. Although it was once thought that there was a scale of nature or a Great Chain of Being, with all the forms of life ascending in some orderly, preordained fashion—from jellyfish to fish to birds to dogs and cats to us—this is not the case. We are not the culmination of all these “lesser” beings; they are not lesser and we are not the pinnacle of evolution. We are not more highly evolved—either physically or mentally—than our closest genetic ancestor, the chimpanzee.‖ Nor, despite the belief of many cat owners, are cats more evolved than dogs. Evolution is not linear. It is divergent—which means that we all sit on the limbs of a bushy tree, each species as evolved as the next, the anatomical differences largely a result of ecology and behavior.
The processes of natural selection have shaped every organism on the tree of life in response to the challenges its ancestors faced. Species that haven’t succeeded are no longer on the bush; they are extinct. That’s why sharks, which have been on earth more than four hundred million years, are considered one of the most successful animals. In comparison, our species, Homo sapiens, has been present for only about two hundred thousand years, and it remains to be seen how long we will last. Our human brains are undeniably more complex anatomically than those of sharks. But sharks have survived throughout the ages because they have evolved brains perfectly designed for how they hunt, find mates, and reproduce in their environment.
Although there is no scale of nature and no Great Chain of Being, I’ve nevertheless organized my book beginning with animals whose brain anatomy is relatively simple and progressing to those that are more complex. I’ve not attempted to summarize everything that researchers now know about a given animal’s cognition. Instead, I’ve selected specific discoveries that illustrate something new about animal minds and that show how scientists studying animal cognition go about their pursuit and why these researchers are drawn to their subjects. The book opens with a visit to an ant lab to illustrate how little neural tissue is required for impressive feats of cognitive processing; and it ends with my meetings with wolf and dog researchers, who are trying to tease apart why some of the cognitive abilities of our canine friends are more similar to those of humans than are those of our closest genetic cousins, the chimpanzees. I had also hoped to visit scientists investigating cats’ mental talents, but unfortunately very few researchers have looked into the feline mind. Those I spoke with emphasized that cats are bright—they’re quick observational learners, for instance—but because cats are independent creatures, getting them to repeat experiments (as is typically required in cognitive studies) is extraordinarily difficult. Immanuel Birmelin, an ethologist at the Society of Animal Behavior Research in Germany, explained how patient he’d had to be in order to run a test to see if cats can count: “One of the cats would do the test once in the morning—only!” he recalled. “Another would do it once in the afternoon—only!” It had taken him four years to show that cats can count to four. Nevertheless, I’ve added descriptions of studies about cats and how they think wherever possible.
As I wrote the book, I struggled with the use of pronouns, specifically whether to use “who” or “that” to identify an animal. It is standard practice to refer to an animal as “that” but I found myself unable to do this. Alex, the gray parrot, was not a “that”—a thing or an object—any more than was Frodo, the chimpanzee, or Betsy, the language-proficient smart dog. In the end, I settled for a halfway measure, using “who” when writing about known individual animals, and “that” for more general cases. It is not a perfect solution, but it does illustrate the larger question and issues we face as we begin to recognize fully the cognitive and emotional natures of animals.
IF YOU’RE MOST INTERESTED in why our human minds are unique, you’ll need to read a different book. I went in search of the minds of animals to better grasp how the other creatures around us perceive and understand the world. What do they think about and how do we know this? Why does it matter? I don’t know if knowing more about animal minds will help improve the lives of humans, although this is usually the rationale scientists, particularly neuroscientists, must use to justify their research. But knowing more about the minds and emotions of other animals may help us do a better job of sharing the earth with our fellow creatures and may even open our minds to new ways of perceiving and thinking about our world.
We live at a time when far too many species are either going extinct or are in grave danger of doing so. Many species are dying or losing their homes and habitats, and the resources they need to survive, because of our actions. We are killing many others, from wild fish to elephants, in unsustainable numbers. As these animals disappear, so do their minds. It is a staggering loss, especially when we consider how unique the act of thinking is. We don’t yet know of another planet that is as endowed with minds as is ours. There may be other planets with life (such a discovery would not surprise me), but as of now, ours is the only one we know about. Yet only in the last few decades have we seriously attempted to find out what is going on in the minds of our fellow creatures, and we’ve studied but a mere handful of the many millions of animal minds on our planet.
SO, HOW DO SCIENTISTS PROVE that an animal is thinking? How do they know that they are showing what an animal can do, and not merely doing what humans do so well: projecting our feelings and thoughts onto something or someone else? All scientists engaged in animal cognition studies worry about this, whether they’re studying insects, dogs, or dolphins. Our human nature wants to empathize, so much so that we give feelings to our cars and computers. And we ache inside for the poor, lone honeybee we’ve just used in a cognitive test and must now kill—to protect the integrity of our research—by humanely placing in a freezer. Can we disentangle our thoughts from such emotions and still find a way to look inside another being’s mind? Can we really understand the minds of the other animals?
People think about this question—perhaps more often than we let on. Just the other day, my husband and I were out hiking with our collie, Buck. A woman walking a Chihuahua approached from the opposite direction. In spite of the difference in their sizes, our two dogs decided they wanted to meet. They were somewhat wary at first, giving each other sideways glances. Then Buck started slowly wagging his tail, as did the Chihuahua. Watching the two, the Chihuahua’s owner asked, “I wonder what they’re thinking?”
It’s a question many of us have surely asked, and it’s the question that drives the scientists in these pages. With new ideas and techniques, they’re finally fully exploring what was once one of the most forbidden realms on earth: the animal mind.
*In 1999, genetic tests showed that Beethoven was Dilly’s father, which suggests that the male chimpanzees somehow do recognize their offspring.
† This short history is by no means meant as a comprehensive discussion of all the thinkers and scientists who in the past have puzzled over the problem of how or if animals think. For the sake of brevity, I’ve mentioned only a handful of the many people who have explored these questions.
‡ Despite this evidence, some people, including some scientists, still object to or have difficulty accepting this simple fact of life. One researcher I interviewed, who studies the mental abilities of humans and dogs, told me that “the biggest problem” he faces is that some of his colleagues in the department of human cognition at his university “don’t think of humans as part of evolution; they don’t fully accept that humans are animals.”
§ Animals and humans are known to develop health issues from stress; they may even die, particularly after losing a mate. There is also increasing acceptance of the idea that social species are badly affected by the loss of a friend or mate. For instance, Laysan albatrosses are monogamous. They nest on Midway Atoll and don’t breed until they are eight or nine years old. If they lose their mate, they “go through a year or two of a mourning period,” says John Klavitter, a U.S. Fish and Wildlife Service biologist at Midway. “After that, they will do a courtship dance to try to find another mate.”
‖ In 1992, the leading neuroscience journal Brain, Behavior and Evolution officially announced the end of the use of the scale of nature in articles discussing the evolution of the brain. It declared that “vague, subjective descriptors such as ‘higher’ and ‘lower’ should be avoided” when referring to animal groups.