My own team typically cajoles, bribes, and sweet-talks its primate partners. Sometimes I feel like a motivational speaker, such as when Peony, one of our oldest females, ignored a task that we had set up for her. For twenty minutes, she lay in the corner. I sat down right next to her and told her, in a calm voice, that I didn’t have all day and it would be great if she would get going. She slowly got up, glancing at me, and strolled to the next room, where she sat down for the task. Of course—as discussed in the previous chapter in relation to Robert Yerkes—it is unlikely that Peony followed the details of what I had said. She was sensitive to my tone of voice and knew all along what we wanted.
However good our relations with apes, the idea that we can test them in exactly the same way we test children is an illusion of the same order as someone throwing both fish and cats into a swimming pool and believing he is treating them the same way. Think of the children as the fish. While testing them, psychologists smile and talk all the time, giving instructions where to look or what to do. “Look at the little froggy!” tells a child so much more than an ape will ever know about the green plastic blob in your hand. Moreover, children are usually tested with a parent in the room, often sitting on their lap. Having permission to run around and an experimenter of their own species, they have an enormous leg up over the ape sitting behind bars without verbal hints or parental support.
True, developmental psychologists try to reduce the influence of parents by telling them not to talk or point, and they may give them sunglasses or a baseball cap to cover their eyes. These measures, however, reveal their woeful underestimation of the power of a parent’s motivation to see their child succeed. When it comes to their precious offspring, few people care about the objective truth. We can be glad that Oskar Pfungst designed far more rigorous controls while examining Clever Hans. In fact, Pfungst found that the wide-rimmed hat of the horse owner greatly benefited Hans, since hats amplify head movements. In the same way that the owner vociferously denied his effect on the horse even after it had been proven, parents of children may be completely honest about suppressing cues. But adults have far too many ways to unintentionally guide the choices of a child on their lap, through slight body movements, gaze direction, halted breathing, sighs, squeezes, strokes, and whispered encouragements. Letting parents attend the testing of a child is asking for trouble—the sort of trouble we avoid in animal testing.
The American primatologist Allan Gardner—who was first to teach American Sign Language to an ape—discussed human biases under the heading “Pygmalion leading.” Pygmalion, in ancient mythology, was a Cypriot sculptor who fell in love with his own statue of a woman. The story has been used as a metaphor of how teachers raise the performance of certain children by expecting the world of them. They fall in love with their own prediction, which serves as a self-fulfilling prophecy. Remember how Charlie Menzel felt that only people who hold apes in high esteem will fully appreciate what they are trying to communicate? His was a plea for raised expectations, which unfortunately is not the situation apes typically face. Children, in contrast, are treated in such a nurturing manner that they inevitably confirm the mental superiority ascribed to them.35 Experimenters admire and stimulate them from the outset, making them feel like fish in the water, whereas they often treat apes more like albino rats: keeping them at a distance, and in the dark, while depriving them of the verbal encouragement we offer members of our own species.
The cognition of children and apes is tested in superficially similar ways. Yet children are not kept behind a barrier; they are talked to and often sit on their parents’ laps, all of which helps them connect with the experimenter and receive unintentional hints. The greatest difference, however, is that only apes face a member of another species. Given how much these comparisons disadvantage one class of subjects, they remain inconclusive.
Needless to say, I view most ape-child comparisons as fatally flawed.36
Recall that apes have been tested for ToM by having them guess what humans know or don’t know. The problem here is that captive apes have every reason to believe that we are omniscient! Suppose my assistant calls to tell me that Socko, the alpha male, has been wounded in a fight. I head over to the field station, walk up to him, and ask him to turn around, which he does—having known me since he was a baby—to show me his behind with the gash. Now try to look at this from Socko’s perspective. Chimps are smart animals, always trying to figure out what’s going on. Of course, he wonders how I know about his injury—I must be an all-knowing god. As such, human experimenters are about the last to be used to find out if apes understand the connection between seeing and knowing. All we are testing is the ape’s theory of the human mind. It is no accident that we made substantial progress only after egg-hunt scenarios pitted apes against other apes.
One area of cognitive research that has been lucky to escape the species barrier is the study of ToM in animals that are so different from us that everyone understands that humans are unsuitable partners. This has been the case with corvids. Since a true animal watcher never takes a break, the British ethologist Nicky Clayton made a major discovery over lunch at the University of California at Davis. While sitting at an outdoor terrace, she saw Western scrub jays fly off with scraps stolen from the tables. They not only cached them but also guarded them against thieves. If another bird saw where they hid their food, it was bound to disappear. Clayton noticed that after their rivals left the scene, many of the jays returned to rebury their treasures. In follow-up research with Nathan Emery in their lab at Cambridge, she let jays cache mealworms either in private or while being watched by another jay. Given a chance, the jays quickly re-cached their worms at a new location—but only if they had been watched. They seemed to understand that the food was safe if no other birds had any information. Moreover, only birds who themselves had pilfered others’ food re-cached their own. Following the dictum “It takes a thief to know a thief,” the jays seemed to extrapolate from their own criminality to that of others.37
A Western scrub jay caches a mealworm while being watched from behind glass by another. As soon as he is alone, the jay will quickly rehide his treasures, as if realizing that the other knows too much.
Again, we recognize the Menzel-like design of this experiment, which is even more obvious in a study of perspective-taking ravens. The Austrian zoologist Thomas Bugnyar had a low-ranking male who was expert at opening canisters that contained goodies, but this male often lost his prize to a bullying and stealing dominant male. The low-ranking male, however, learned to distract his competitor by enthusiastically opening empty containers and making as if to eat from them. When the dominant bird found out, “he got very angry, and started throwing things around.” Bugnyar further found that when ravens approach hidden food, they take into account what other ravens know. If their competitors have the same knowledge, they hurry to get there first. But if the others are ignorant, they take their time.38