Today, when I should have already begun researching for my dissertation idea paper, I was just getting up from brunch when the PBS Nova series began. Expecting another episode on nebulas or colliding galaxies, I started from my chair. But then I saw that the topic was ape intelligence, specifically, what accounts for the differences between human intelligence and that of our closest primate relatives. I am nearly defenseless when it comes to resisting programs or articles on this topic. Whatever else I had intended to do falls by the way. (I really need to complete that PVR project I started a few months ago, so that I can schedule to record such programs for later viewing.)

The most interesting upshot from the program was that while both apes and humans can imitate, only humans actively teach and seek to be taught. This has some interesting effects. For one, apes are intensely focused on life-sustainment objectives, such as getting the next bit of food. When watching a human demonstrate how to extract food from a man-made contraption, the apes readily distinguish the essential steps from the superfluous ones. By contrast, human four-year-olds mimic every step demonstrated by an adult, even though some of the steps are obviously (to older humans) irrelevant to obtaining the treat. The experiment was first conducted with an opaque device, so that neither apes nor humans could tell whether the demonstrated behaviors had any mechanical effect inside the box that contained the food. In this case, apes and human children mimicked all observed actions. In the second phase, an identical but transparent box was used. The apes (chimps, in this case) immediately recognized that several of the demonstrated actions were irrelevant to obtaining the food. The chimps skipped those steps. The human children, however, were primed to accept the adult human’s demonstrated behavior as valid in its entirety. Without questioning or experimenting, the children continued executing the goal-irrelevant steps along with the goal-essential steps. Or, perhaps, it is more correct to say that the goal of the children was not limited to obtaining the snack. Rather, for human four-year-olds, the overarching goal of learning is to imitate the teacher as completely as possible.

Such could at least partially explain the human capacity to teach and learn elaborate belief and behavioral systems that include so much irrelevant (and even downright dumb) details. When I saw the children unquestioningly waving sticks and tapping the food box with the sticks, not because of any actual effect on opening the box, but just because the adult mentor had done so, I immediately thought of the endless traditions and superstitious practices humans propagate through our cultures. I also thought of the type of story management gurus have used to highlight mindless mimicry. One is the turkey tail story, in which a young girl, seeing her mother cut the tail off of a turkey before placing it a baking pan, asks her mother, “Why did you cut off its tail?” The mother replies, “because my Mom always does that.” The little girl goes into the next room and asks her grandmother, “Gramma, why did you always cut off the turkey’s tail?” The grandmother replies, “Because that’s how my mother did it, and she never did anything that wasn’t necessary.” So later in the day, when great-grandmother arrives, the girls repeats the question to the matriarch. Great grandma answers, “Honey, my baking pan was too small for the turkey great grandpa brought home, so I had to cut off the tail to get the turkey to fit.” Silly though they sound, such stories highlight the human penchant for turning isolated behaviors, that once had a purpose, into unquestioned traditions. It appears, then, that one of the keys of human intelligence — unquestioning mimicry — may also be one of the key limitations to innovation.

NOVA | Ape Genius | The Ape That Teaches | PBS