Similar understanding can be seen in their altruism, such as when younger females collect water in their mouths for an aging female, who can barely walk anymore, spitting it into her open mouth so that she doesn’t have to walk all the way to the spigot. The British primatologist Jane Goodall described how Madame Bee, a wild chimpanzee, had become too old and weak to climb into fruiting trees. She would patiently wait at the bottom for her daughter to carry down fruits, upon which the two of them would contentedly munch together.5 In such cases, too, apes grasp a problem and come up with a fresh solution, but the striking part here is that they perceive another ape’s problem. Since these social perceptions have attracted much research, we’ll delve into them later on, but let me clarify one general point about problem solving. Although K?hler stressed that trial-and-error learning could not explain his observations, it was not as if learning played no role at all. In fact, his apes committed tons of “stupidities,” as K?hler called them, that showed that solutions were rarely perfectly formed in their minds and required quite a bit of tweaking.
His apes had undoubtedly learned the affordances of various items. This term from cognitive psychology refers to how objects can be used, such as the handle on a teacup (which affords holding) or the steps on a ladder (which afford climbing). Sultan must have known the affordances of sticks and boxes before he hit on his solutions. Similarly, the female chimp who activated Mama had no doubt witnessed the latter’s effectiveness as arbitrator. Insightful solutions invariably rest on prior information. What is special about apes is their capacity to flexibly weave such preexisting knowledge into new patterns, never tried before, that work to their advantage. I have speculated the same about their political strategies, such as the way chimps will isolate a rival from his supporters or encourage a truce by dragging reluctant former combatants toward each other.6 In all such cases, we see apes finding insightful solutions to everyday problems. They are so good at it that even the staunchest skeptic, as Menzel discovered, finds it impossible to watch them without being struck by their obvious intentionality and intelligence.
Wasp Mugs
There was a time when scientists thought behavior derived from either learning or biology. Human behavior was on the learning side, animal behavior on the biology side, and there was little in between. Never mind the false dichotomy (in all species, behavior is a product of both), but increasingly a third explanation had to be added: cognition. Cognition relates to the kind of information an organism gathers and how it processes and applies this information. Clark’s nutcrackers remember where they have stored thousands of nuts, beewolves make an orientation flight before leaving their burrow, and chimpanzees nonchalantly learn the affordances of play objects. Without any reward or punishment, animals accumulate knowledge that will come in handy in the future, from finding nuts in the spring, to returning to one’s burrow, to reaching a banana. The role of learning is obvious, but what is special about cognition is that it puts learning in its proper place. Learning is a mere tool. It allows animals to collect information in a world that, like the Internet, contains a staggering amount of it. It is easy to drown in the information swamp. An organism’s cognition narrows down the information flow and makes it learn those specific contingencies that it needs to know given its natural history.
Many animals have cognitive achievements in common. The more scientists discover, the more ripple effects we notice. Capacities that were once thought to be uniquely human, or at least uniquely Hominoid (the tiny primate family of humans plus apes), often turn out to be widespread. Traditionally, apes have been the first to inspire discoveries thanks to their manifest intellect. After the apes break down the dam between humans and the rest of the animal kingdom, the floodgates often open to include species after species. Cognitive ripples spread from apes to monkeys to dolphins, elephants, and dogs, followed by birds, reptiles, fish, and sometimes invertebrates. This historical progression is not to be confused with a scale with Hominoids on top. I rather view it as an ever-expanding pool of possibilities in which the cognition of, say, the octopus may be no less astonishing than that of any given mammal or bird.
Paperwasps live in small hierarchical colonies in which it pays to recognize every individual. Their black-and-yellow facial markings allow them to tell one another apart. A closely related wasp species with a less differentiated social life lacks face recognition, which shows how much cognition depends on ecology.
Consider face recognition, which was initially viewed as uniquely human. Now apes and monkeys have joined the countenance elite. Every year when I visit Burgers’ Zoo, in Arnhem, a few chimps still remember me from more than three decades before. They pick out my face from the crowd, greeting me with excited hooting. Not only do primates recognize faces, but faces are special to them. Like humans, they show an “inversion effect”: they have trouble recognizing faces that are turned upside down. This effect is specific for faces; how an image is oriented hardly matters for the recognition of other objects, such as plants, birds, or houses.
When we tested capuchin monkeys using touchscreens, we noticed that they freely tapped all sorts of images, but they freaked out at the first face that appeared. They clutched themselves and whined, reluctant to touch the picture. Did they treat it with more respect because putting a hand on a face violates a social taboo? Once they got over their hesitation, we showed them portraits of group mates and unknown monkeys. All these portraits look alike to na?ve humans since they concern the same species, but our monkeys had no trouble telling them apart, indicating with a little tap on the screen which ones they knew and which ones they didn’t.7 We humans take this ability for granted, but the monkeys had to link a two-dimensional pattern of pixels to a live individual in the real world, which they did. Face recognition, science concluded, is a specialized cognitive skill of primates. But no sooner had it done so than the first cognitive ripples arrived. Face recognition has been found in crows, sheep, even wasps.
It is unclear what faces mean to crows. In their natural lives, they have so many other ways of recognizing one another by calls, flight patterns, size, and so on, that faces may not be relevant. But crows have incredibly sharp eyes, so they likely notice that humans are easiest recognized by their faces. Lorenz reported harassment of certain people by crows and was so convinced of their ability to hold a grudge that he disguised himself with a costume whenever he captured and banded his jackdaws. (Both jackdaws and crows are corvids, a brainy bird family that also includes jays, magpies, and ravens.) Wildlife biologist John Marzluff at the University of Washington, in Seattle, has captured so many crows that these birds take his name in vain whenever he walks around, scolding and dive-bombing him, doing justice to the “murder” label used for a whole bunch of them.
We don’t know how they pick us out of the forty thousand folk scurrying like two-legged ants over well-worn trails. But single us out they do, and nearby crows flee while uttering a call that sounds to us like vocal disgust. In contrast, they calmly walk among our students and colleagues who have never captured, measured, banded, or otherwise humiliated them.8