One aspect we might focus on during this moratorium is an alternative to overly cerebral approaches. I have already mentioned that perspective taking is likely tied to bodies, and the same applies to imitation. After all, imitation requires that another individual’s body movements are perceived and translated into one’s own body movements. Mirror neurons (special neurons in the motor cortex that map another’s actions onto one’s own bodily representations in the brain) are often thought to mediate this process, and it is good to realize that those neurons were discovered not in humans but in macaques. Even though the precise connection remains a point of debate, imitation likely is a bodily process facilitated by social closeness.
This view is quite different from the cerebral one according to which it all depends on the understanding of cause-effect relations and goals. Thanks to an ingenious experiment by the British primatologist Lydia Hopper, we know which view is correct. Hopper presented chimps with a so-called ghost box controlled by fishing lines. The box magically opened and closed by itself, producing rewards. If technical insight were all that mattered, watching such a box should suffice, as it shows all the necessary actions and consequences. But in fact, letting chimps watch the ghost box ad nauseam taught them nothing. Only after seeing an actual chimp operate the same box, did they learn how to get the rewards.59 Thus for imitation to occur, apes need to connect to a moving body, preferably one of their own species. Technical understanding is not the key.60
To find out how bodies interact with cognition, we have incredibly rich material to work with. Adding animals to the mix is bound to stimulate the up-and-coming field of “embodied cognition,” which postulates that cognition reflects the body’s interactions with the world. Until now, this field has been rather human-focused while failing to take advantage of the fact that the human body is only one of many.
Consider the elephant. It combines a very different body with the brainpower to achieve high cognition. What is the largest land mammal doing with three times as many neurons as our own species? One may downplay this number, arguing that it has to be corrected for body mass, but such corrections are more suited to brain weight than to number of neurons. In fact, it has been proposed that absolute neuron count, regardless of brain or body size, best predicts a species’ mental powers.61 If so, we’d better pay close attention to a species that has vastly more neurons than we do. Since most of these neurons reside in the elephant’s cerebellum, some feel they carry less weight, the assumption being that only the prefrontal cortex matters. But why take the way our brain is organized as the measure of all things and look down on subcortical areas?62 For one thing, we know that during Hominoid evolution, our cerebellum expanded even more than our neocortex. This suggests that for our species, too, the cerebellum is critically important.63 It is now up to us to find out how the remarkable neuron count of the elephant brain serves its intelligence.
The trunk, or proboscis, is an extraordinarily sensitive smelling, grasping, and feeling organ said to contain forty thousand muscles coordinated by a unique proboscis nerve that runs along its full length. The trunk has two sensitive “fingers” at the tip, with which it can pick up items as small as a blade of grass, but the trunk also allows the animal to suck up eight liters of water or flip over an annoying hippo. True, the cognition associated with this appendage is specialized, but who knows how much of our own cognition is tied to the specifics of our bodies, such as our hands? Would we have evolved the same technical skills and intelligence without these supremely versatile appendages? Some theories of language evolution postulate its origin in manual gestures as well as in neural structures for the throwing of stones and spears.64 In the same way that humans have a “handy” intelligence, which we share with other primates, elephants may have a “trunky” one.
There is also the issue of continued evolution. It is a widespread misconception that humans kept evolving while our closest relatives stopped. The only one who stopped, however, is the missing link: the last common ancestor of humans and apes, so named because it went extinct long ago. This link will forever remain missing unless we happen to dig up some fossil remains. I named my research center Living Links, in a wordplay on the missing link, since we study chimpanzees and bonobos as live links to the past. The name has caught on, because there are now a few other Living Links centers in the world. Traits shared across all three species—our two closest ape relatives and ourselves—likely have the same evolutionary roots.
But apart from commonalities, all three species also evolved in their own separate ways. Since there is no such thing as halted evolution, all three probably changed substantially. Some of these evolutionary changes gave our relatives an advantage, such as the resistance to the HIV-1 virus that evolved in West African chimps long before the AIDS epidemic devastated humanity.65 Human immunity has some serious catching up to do. Similarly, all three species—not just ours—had time to evolve cognitive specializations. No natural law says that our species has to be best at everything, which is why we should be prepared for more discoveries such as Ayumu’s flash memory or the selective imitative talents of apes. A Dutch educational program recently brought out an advertisement in which human children face the floating peanut task (see Chapter 3). Even though the members of our species have a bottle of water standing not too far away, they fail to think of the solution until they see a video of apes solving the same problem. Some apes do so spontaneously, even when there is no bottle around to suggest what to do. They walk to the faucet where they know water can be collected. The point of the ad is that schools should teach kids to think outside the box, using apes as an inspiration.66
The more we know about animal cognition, the more examples of this kind may come to light. The American primatologist Chris Martin, at the PRI in Japan, has added yet another chimpanzee forte. Using separate computer screens, he had apes play a competitive game that required them to anticipate one another’s moves. Could they outguess their rivals based on their previous choices, a bit like the rock-paper-scissors game? Martin had humans play the same game. The chimps outperformed the humans, reaching optimal performance more quickly and completely than members of our own species. The scientists attributed the edge to chimps being quicker at predicting a rival’s moves and countermoves.67