Are We Smart Enough to Know How Smart Animals Are? (37 page)

Conformism is hard to substantiate in the field. There are too many alternative explanations for why one individual might act like another, including genetic and ecological ones. How these issues can be resolved was shown by a large-scale project on humpback whales in the Gulf of Maine in the northeastern United States. In addition to their regular bubble-feeding, in which whales drive fish together with air bubbles, one male invented a new technique. First seen in 1980, this whale would whack the ocean surface with his fluke to produce a loud noise that clumped the prey even more. Over time this lobtail technique became increasingly common in the population. In the course of a quarter-century, investigators carefully plotted how it spread across six hundred individually recognized whales. They found that whales who had associated with those employing the technique were more likely to use it themselves. Kinship could be ruled out as a factor, because whether a whale had a lobtail-feeding mother hardly mattered. It all boiled down to whom they had encountered while feeding on fish. Since large cetaceans are unsuitable for experiments, this may be as close as we will ever get to proving that a habit spread socially as opposed to genetically.
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On wild primates, experimental work is rare for different reasons. First of all, these animals are neophobic, and rightly so, because imagine the danger of freely approaching human contraptions, including those set by poachers. Second, fieldworkers generally hate to expose their animals to artificial situations, since their goal is to study them with as little disturbance as possible. Third, they have no control over who participates in an experiment and for how long, thus precluding the kind of tests typically applied to animals in captivity.

So one has to admire one of the most elegant experiments on conformism on wild monkeys, carried out by the Dutch primatologist Erica van de Waal (no relation).
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Teaming up with Andy Whiten, who has been an engine of cultural studies, van de Waal gave vervet monkeys in a South African game reserve open plastic boxes filled with maize corn. These small grayish monkeys with black faces love corn, but there was a catch: the scientists had manipulated the supply. There were always two boxes with two colors of corn, blue and pink. One color was good to eat whereas the other was laced with aloe, making it disgusting. Depending on which color corn was palatable, and which not, some groups learned to eat blue, and others pink.

This preference is easily explained by associative learning. But then the investigators removed the distasteful treatment and waited for infants to be born and new males to immigrate from neighboring areas. They watched several groups of monkeys that were supplied with perfectly fine corn of both colors. All adults stubbornly stuck to their acquired preference, however, and never discovered the improved taste of the alternative color. Twenty-six of twenty-seven newborn infants learned to eat only the locally preferred food. Like their mothers, they didn’t touch the other color, even though it was freely available and just as good as the other. Individual exploration was obviously suppressed. The youngsters might even sit on top of the box with the rejected corn while happily feeding on the other type. The single exception was an infant whose mother was so low in rank, and so hungry, that she occasionally tasted the forbidden fruits. Thus, all newborns copied their mothers’ feeding habits. Male immigrants, too, ended up adopting the local color even if they arrived from groups with the opposite preference. That they switched their preference strongly suggests conformism, since these males knew from experience that the other color was perfectly edible. They simply followed the adage “When in Rome …”

These studies prove the immense power of imitation and conformism. It is not a mere extravagance that animals occasionally engage in for trivial reasons—which, I hate to say, is how animal traditions have sometimes been derided—but a widespread practice with great survival value. Infants who follow their mother’s example of what to eat and what to avoid obviously stand a better chance in life than infants who try to figure out everything on their own. The idea of conformism among animals is increasingly supported for social behavior as well. One study tested both children and chimpanzees on generosity. The goal was to see if they were prepared to do a member of their own species a favor at no cost to themselves. They indeed did so, and their willingness increased if they themselves had received generosity from others—
any
others, not just their testing partner. Is kind behavior contagious? Love begets love, we say, or as the investigators put it more dryly, primates tend to adopt the most commonly perceived responses in the population.
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The same can be concluded from an experiment in which we mixed two different macaques: rhesus and stumptail monkeys. Juveniles of both species were placed together, day and night, for five months. These macaques have strikingly different temperaments: rhesus are a quarrelsome, nonconciliatory bunch, whereas stumptails are laid-back and pacific. I sometimes jokingly call them the New Yorkers and Californians of the macaque world. After a long period of exposure, the rhesus monkeys developed peacemaking skills on a par with those of their more tolerant counterparts. Even after separation from the stumptails, the rhesus showed nearly four times more friendly reunions following fights than is typical of their species. These new and improved rhesus monkeys confirmed the power of conformism.
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One of the most intriguing sides of social learning—defined as learning from others—is the secondary role of reward. While individual learning is driven by immediate incentives, such as a rat learning to press a lever to obtain food pellets, social learning doesn’t work this way. Sometimes conformism even
reduces
rewards—after all, the vervet monkeys missed out on half of the available food. We once conducted an experiment in which capuchin monkeys watched a monkey model open one of three differently colored boxes. Sometimes the boxes contained food, but at other times they were empty. It didn’t matter: the monkeys copied the model’s choices regardless of whether there was any reward.
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There are even examples of social learning in which the benefits, instead of going to the performer, go to someone else. At the Mahale Mountains in Tanzania, I regularly saw a chimpanzee walk up to another, vigorously scratch the other’s back with his or her fingernails, then settle down to groom the other. In between the grooming, more scratching might follow. This behavior has been known for a long time and has thus far been reported for only one other field site. It is a locally learned tradition, but here’s the rub: when one scratches oneself, it is usually due to itching, and the act brings instant relief. In the case of the social scratch, however, the performer does not feel relief—the recipient does.
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Primates occasionally learn habits from others that do pay off, such as when chimpanzee youngsters learn to crack nuts with stones. But even then things are not as simple as they appear. Sitting next to their nut-cracking moms, infant chimps are total klutzes. They put nuts on top of stones, stones on top of nuts, and push them all together in a heap only to rearrange them over and over. They gain nothing from this playful activity. They also hit nuts with a hand, or stamp them hard with a foot, which fails to crack anything. Palm and panda nuts are far too tough for them. Only after three years of futile efforts do young chimps have enough coordination and strength to break open their first nut with a pair of stones, but they still have to wait until they are six or seven to reach adult skill levels.
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Since they utterly fail at this task for so many years in a row, it is unlikely that food is the incentive. They may even experience negative consequences, such as smashed fingers. Yet young chimps happily persist, inspired by the example of their elders.

How little rewards matter is also evident from habits that lack benefits. In our own species, we have fads such as wearing a baseball cap backward or pants that hang low enough to impede locomotion. But in other primates, too, we find seemingly useless fashions and habits. A nice example is the N-family in a group of rhesus monkeys that I observed long ago at the Wisconsin Primate Center. This matriline was headed by an aging matriarch, Nose, all of whose offspring had names starting with the same letter, such as Nuts, Noodle, Napkin, Nina, and so on. Nose had developed the odd routine of drinking from a water basin by dipping her entire underarm into it, then licking her hand and the hair on her arm. Amusingly, all her offspring, and later her grandchildren adopted the exact same technique. No other monkeys in the troop, or any other that I knew, drank like this, yet there was absolutely no advantage to it. It did not allow the N-family to access anything that other monkeys had no access to.

Or take the way chimpanzees sometimes develop local dialects, such as the excited grunts uttered while snacking on tasty food. These grunts differ not only from group to group but also per food type, such as a particular grunt heard only while they eat apples. When the Edinburgh Zoo introduced chimpanzees from a Dutch zoo to its residents, it took those others three years to get socially integrated. Initially, the newcomers uttered different grunts while eating apples, but by the end they converged on the same grunts as the locals. They had adjusted their calls so that they sounded more like those of the residents. While the media hyped this finding by saying that Dutch chimps had learned to speak Scottish, it was more like picking up an accent. The bonding between individuals of different backgrounds had resulted in conformism, even though chimps are not particularly known for vocal flexibility.
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Clearly, social learning is more about fitting in and acting like others than about rewards. This is why my book on animal culture was entitled
The Ape and the Sushi Master
. I chose this title partly to honor Imanishi and the Japanese scientists who gave us the animal culture concept, but also because of a story I had heard about how apprentice sushi masters learn their trade. The apprentice slaves in the shadow of the master of an art requiring rice of the right stickiness, precisely cut ingredients, and the eye-catching arrangements for which Japanese cuisine is famous. Anyone who has ever tried to cook rice, mix it with vinegar, and cool it off with a handheld fan so as to mold fresh rice balls in one’s hands knows how complex a skill it is, and it is only a small part of the job. The apprentice learns mostly through passive observation. He washes the dishes, mops the floor, bows to the clients, fetches ingredients, and in the meantime follows from the corners of his eyes, without ever asking a question, everything the sushi master does. For three years he watches without being allowed to make actual sushi for the patrons of the restaurant: an extreme case of exposure without practice. He is waiting for the day when he will be invited to make his first sushi, which he will do with remarkable dexterity.

Whatever the truth about the sushi master’s education, the point is that repeated observation of a skilled model firmly plants action sequences in one’s head that come in handy, sometimes much later, when one needs to carry out the same task. Tetsuro Matsuzawa, who studied nut-cracking in West African chimpanzees, views social learning as based on a devoted master-apprentice relationship, in the same way that I developed my Bonding- and Identification-based Observational Learning model (BIOL).
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Both views reject the traditional focus on incentives and replace it with one on social connections. Animals strive to act like others, especially others whom they trust and feel close to. Conformist biases shape society by promoting the absorption of habits and knowledge accumulated by previous generations. This by itself is obviously advantageous—and not just in the primates—so even though conformism is not driven by immediate benefits, it likely assists survival.

What’s in a Name?

Konrad Lorenz was a big corvid fan. He always kept jackdaws, crows, and ravens around his house in Altenberg, near Vienna, and considered them the birds with the highest mental development. In the same way that I, as a student, took walks with my tame jackdaws flying above me, he traveled with Roah, his old raven and “close friend.” And like my jackdaws, the raven would come down from the sky and try to make Lorenz follow by moving his tail sideways before him. It is a quick gesture that is not easily noticed from a distance yet hard to miss if done right in front of your face. Curiously, Roah used his own name to call Lorenz, whereas ravens normally call one another with a sonorous, deep-throated call-note described by Lorenz as a metallic “krackkrackkrack.” Here is what he said about Roah’s invitations:

Roah bore down on me from behind, and, flying close over my head, he wobbled with his tail and then swept upwards again, at the same time looking backwards over his shoulder to see if I was following. In accompaniment of this sequence of movements Roah, instead of uttering the above described call-note, said his own name, with human intonation. The most peculiar thing about this was that Roah used the human word for me only. When addressing one of his own species, he employed the normal innate call-note.
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Lorenz denied that he had taught his raven to call like this—after all, he had never rewarded him for it. He suspected that Roah must have inferred that since “Roah!” was the call-note Lorenz used for him, it might also work in reverse. This sort of behavior may appear in animals that contact one another vocally and are moreover great imitators. As we shall see, this also holds for dolphins. In the primates, on the other hand, individual identity is usually visually determined. The face is the most characteristic part of the body; hence face recognition is highly developed and has been demonstrated in multiple ways in both monkeys and apes.

It is not just faces that they pay attention to, however. During our studies, we discovered how intimate chimps are with one another’s derrières. In one experiment, they first saw a picture of the behind of one of their group mates followed by two facial pictures. Only one of both faces belonged to the behind, however. Which one would they select on the touchscreen? It was a typical matching-to-sample task of the type invented by Nadia Kohts before the computer age. We found that our apes selected the correct portrait, the one that went with the butt they had seen. They were only successful, though, with chimps that they knew personally. That they failed with pictures of strangers suggests that it was not based on something in the pictures themselves, such as color or size. They must possess a whole-body image of familiar individuals, knowing them so well that they can connect any part of their body with any other part.