Are We Smart Enough to Know How Smart Animals Are? (30 page)

What is time? Leave now for dogs and apes! Man has forever!

—Robert Browning (1896)
¹

J
udging the gap between two trees, a monkey relies on its memory of past jumps to calculate the next one. Is there a landing spot on the other side? Is it within jumping distance? Can the branch handle its impact? These life-and-death decisions take a great deal of experience to make and show how past and future intertwine in a species’s behavior. The past provides the required practice, whereas the future is where the next move will take place. Long-range future orientation is also common, such as when during a drought the matriarch of an elephant herd remembers a drinking hole miles away that no one else knows about. The herd sets out on a long trek, taking days to reach precious water. While the matriarch operates on the basis of knowledge, the rest of the herd operates on the basis of trust. Whether it is a matter of seconds or days, animal behavior is not only goal- but also future-oriented.

So it is curious to me that animals are often thought to be stuck in the present. The present is ephemeral. One moment it is here, the next it is gone. Whether you are a thrush picking up a worm for your chicks in a distant nest or a dog setting out in the morning to patrol your territory and dribble urine at strategic locations, animals have jobs to do, which imply the future. True, most of the time it is the near future, and it remains unclear how aware they are of it. Yet their behavior would make no sense if they lived entirely in the present.

We ourselves consciously reflect on the past and the future, so it was perhaps unavoidable that whether animals do or don’t would become a battleground. Isn’t consciousness what sets humans apart? Some claim that we are the only ones to actively recall the past and imagine the future, but others have been busy gathering evidence to the contrary. Since no one can prove conscious reflection without verbal reports, the debate skirts subjective experience as something that—at least for now—we can’t put our finger on. There has been genuine progress, though, in the exploration of how animals relate to the time dimension. Of all areas of evolutionary cognition, this one is perhaps the most esoteric and the hardest to get a handle on. The terminology shifts regularly, and debates are fierce. For this reason, I have visited two experts to ask them where we currently stand, which opinions will be presented at the end of this chapter.

In Search of Lost Time

Perhaps the controversy started earlier than we think, because in the 1920s an American psychologist, Edward Tolman, bravely and controversially asserted that animals are capable of more than the mindless linking between stimulus and response. He rejected the idea of them as purely incentive-driven. He dared use the term
cognitive
(he was famous for his studies of cognitive maps in maze-learning rats) and called animals “purposive,” guided by goals and expectations, both of which reference the future.

While Tolman—in a bow to the suffocating grip of the era’s classical behaviorism—shied away from the stronger term
purposeful
, his student Otto Tinklepaugh designed an experiment in which a macaque watched either a lettuce leaf or a banana being placed under a cup. As soon as the monkey was given access, she ran to the baited cup. If she found the food that she had seen being hidden, everything proceeded smoothly. But if the experimenter had replaced the banana with lettuce, the monkey only stared at the reward. She’d frantically look around, inspecting the location over and over, while angrily shrieking at the sneaky experimenter. Only after a long delay would she settle for the disappointing vegetable. From a behaviorist perspective, her attitude was bizarre since animals are supposed to merely connect behavior with rewards,
any
rewards. The nature of the reward shouldn’t matter. Tinklepaugh, however, demonstrated that there is more going on. Guided by a mental representation of what she had seen being hidden, the monkey had developed an expectation, the violation of which deeply upset her.
²

Instead of merely preferring one behavior over another, or one cup over another, the monkey recalled a specific event. It was as if she were saying “Hey, I swear I saw them put a banana under that cup!” Such precise recall of events is known as
episodic memory
, which was long thought to require language, hence to be uniquely human. Animals were thought to be good at learning the general consequences of behavior without retaining any specifics. This position has become shaky, though. Let me give an example that is a bit more striking since it involves a much longer time frame than the monkey experiment.

We once applied a Menzel-type test to Socko, when he was still an adolescent chimpanzee. Through a small window, Socko watched my assistant hide an apple in a large tractor tire in the outdoor enclosure, while the rest of the colony was kept behind closed doors. Then we released the colony, holding Socko back until last. The first thing he did after coming out the door was to climb onto the tire and peek into it, checking on the apple. He left it alone, though, and nonchalantly walked away from the scene. He waited for more than twenty minutes, until everyone was otherwise occupied, and then went to collect the fruit. This was clever, since he might otherwise have lost his prize.

The truly interesting twist came years later, however, when we repeated this experiment. Socko had been tested only once, and we showed the video to a visiting camera crew. But as is typical, the crew trusted its own filming better and insisted on redoing the whole test. By this time Socko was the alpha male and hence could not be used anymore. Being of high rank, he would have had no reason to conceal what he knew about hidden food. So instead we selected a low-ranking female named Natasha and did everything nearly same. We locked up all the chimps and let Natasha watch through the window while we hid an apple. This time we dug a hole in the ground, put the apple into it, and covered it with sand and leaves. We did this so well that afterward we barely knew where we’d put the fruit.

After the others were released, Natasha finally entered the enclosure. We waited anxiously, following her with several cameras. She showed a pattern similar to Socko’s and moreover displayed a far better sense of location than we did. She passed slowly over to the precise hiding spot, then returned ten minutes later to confidently dig up the fruit. While she did so, Socko stared at her with apparent surprise. It is not every day that someone pulls an apple out of the ground! I worried that Socko might punish her for snacking right in front of him, but no, Socko ran straight to the tractor tire! He looked into it from several angles, but obviously it was empty. It was as if he had concluded that we were hiding fruit again—and he recalled the exact location we’d used before. This was most remarkable since I am pretty sure Socko had had only one experience of this kind in his whole life, which had occurred five years earlier.

Was this mere coincidence? It is hard to tell based on a single event, but fortunately a Spanish scientist, Gema Martin-Ordas, has been testing out this sort of memory. Working with a large number of chimpanzees and orangutans, she tested the apes on what they remembered of past events. Previously, the apes had been given a task that required them to find the right tool to fetch either a banana or frozen yogurt. The apes had watched tools being hidden in boxes, after which they needed to pick the right box to get a tool for the task. This being easy for apes, all went well. But three years later, after the apes had gone through scores of other events and tests, they all of a sudden encountered the same person, Martin-Ordas, presenting the same setup in the same rooms of the building. Would the presence of the same investigator and situation cue the apes about the challenge they faced? Would they know right away what tool to use and where to look for it? They did, or at least those with previous experience did. Naïve apes did nothing of the kind, thus confirming the role of memory. And not only that, the apes did not hesitate: they solved the problem in a matter of seconds.
³

Most animal learning is of a rather vague kind, similar to how I have learned to avoid some Atlanta highways at certain times of the day. Having gotten stuck in traffic often enough, I will look for a better, faster route, without any specific memory of what happened on my previous commutes. This is also how a rat in a maze learns to turn one way and not another, and how a bird learns at what time of day to find bread crumbs at my parents’ balcony. This kind of learning is all around us. What we deem a special kind, the one at issue here, is the recall of particulars, the way the French novelist Marcel Proust, in
In Search of Lost Time
dwelled on the taste of a
petite madeleine
. The little tea-soaked biscuit made him relive his childhood visits to Aunt Leonie: “No sooner had the warm liquid mixed with the crumbs touched my palate than a shudder ran through me and I stopped, intent upon the extraordinary thing that was happening to me.”
⁴
The power of autobiographical memories lies in their specificity. Colorful and alive, they can be actively called up and dwelled upon. They are reconstructions—which is why they are sometimes false—yet so powerful that they are accompanied by an extraordinary sense of their correctness. They fill us with emotions and sensations, as happened to Proust. You mention someone’s wedding day, or Dad’s funeral, and all sorts of memories about the weather, the guests, the food, the happiness, or the sadness will flood the mind.

This kind of memory must be at work when apes react to cues connected to events from years back. The same memory serves foraging wild chimpanzees, which visit about a dozen fruit-bearing trees per day. How do they know where to go? The forest has far too many trees to go about it randomly. Working in Taï National Park, in Ivory Coast, the Dutch primatologist Karline Janmaat found apes to have an excellent recall of previous meals. They mostly checked trees at which they had eaten in previous years. If they ran into copious ripe fruit, they’d gorge on it while grunting contentedly and make sure to return a couple of days later.

Janmaat describes how the chimps would build their daily nests (in which they sleep for only one night) en route to such trees and get up before dawn, something they normally hate to do. The intrepid primatologist followed the traveling party on foot, but whereas the chimps typically ignored her tripping or stepping on a noisy branch, now they all would turn around and stare pointedly at her, making her feel bad. Sounds draw attention, and the chimps were on edge in the dark. This was understandable since one of the females had recently lost her infant to a leopard.

Despite their deep-seated fear, the apes would set out on a long trek to a specific fig tree where they had recently eaten. Their goal was to beat the early fig rush. These soft, sweet fruits are favored by many forest animals, from squirrels to flocks of hornbills, so that an early arrival would be the only way to take advantage of the abundance. Remarkably, the chimps would get up earlier for trees far from their nests than for those nearby, arriving at about the same time at both. This suggests calculation of travel time based on expected distances. All this makes Janmaat believe that the Taï chimpanzees actively recall previous experiences in order to plan for a plentiful breakfast.
⁵

The Estonian-Canadian psychologist Endel Tulving defined
episodic memory
as the recall of what happened at which place and at what time. This has prompted research into memory of the three
W
’s of events: their what, when, and where.
⁶
While the above ape examples seem to fit the bill, we need more tightly controlled experiments. The first challenge to Tulving’s claim that episodic memory is limited to humans came from precisely such an experiment, not on apes, but on birds. Together with Anthony Dickinson, Nicky Clayton took advantage of the hoarding tendency of her western scrub jays to see what they remembered about cached foods. The birds were given different items to hide, some perishable (waxworms), others durable (peanuts). Four hours later the jays looked for the worms—their favorite food—before they looked for nuts, but five days later their response was reversed. They didn’t even bother to find the worms, which by that time would have spoiled and become distasteful. They did remember the peanut locations after this long interval, though. Odor could be ruled out as a factor, because by the time they were tested, the scientists recorded search patterns in the absence of food. This study was quite ingenious and included a few additional controls, leading the authors to conclude that jays recall what items they have put where and at what point in time. They remembered the three
W
’s of their actions.
⁷

The case for episodic memory in animals was further strengthened when the American psychologists Stephanie Babb and Jonathon Crystal let rats run around in an eight-armed radial maze. The rodents learned that once they had visited an arm and eaten the food in it, it would be permanently gone, so there would be no point returning to it. There was one exception, though. They occasionally found chocolate-flavored pellets, which would be replenished after long time intervals. The rats formed an expectation about this delicious food based on where and when they had encountered it. They did return to those specific arms, but only after long intervals. In other words, the rodents kept track of the when, what, and where of chocolate surprises.
⁸

Tulving and a few other scholars were hardly satisfied with these results, however. They fail to tell us—the way Proust did so eloquently—how aware the birds, rats or apes are of their own memories. What kind of consciousness, if any, is involved? Do they view their past as a piece of personal history? Since such questions are unanswerable, some have weakened the terminology by endowing animals only with “episodic-like” memory. I don’t agree with this retreat, however, since it gives weight to an ill-defined aspect of human memory known only through introspection and language. While language is helpful to communicate memories, it is hardly what produces them. My preference would be to turn the burden of proof around, especially when it comes to species close to us. If other primates recall events with equal precision as humans do, the most economic assumption is that they do so in the same way. Those who insist that human memory rests on unique levels of awareness have their work cut out for them to substantiate such a claim.