Cognitive scientists—even ones who are interested in child development—generally speaking, their interest is in the brain. But the brain is intimately connected to the hand.

Cognitive scientists—even ones who are interested in child development—generally speaking, their interest is in the brain. And, if you start talking about the hand, they will say, “Well, I know that the hand is very good in tool use and so forth, but you can see examples in other animals. Parrots can do this and chimpanzees can do that.” But, the fact of the matter is that for the most part, unless they have actually studied the upper extremity anatomically and in terms of its function; how grips are formed, how a child, for example, learns to control the frictional forces of an object that is slippery—unless they come to understand that and they really understand the details of it, they are simply going to gloss over the fact that, “Well, you know we have a long opposable thumb and we have the ability to independently control the movement of the digits, but you know, that’s not that different from what chimpanzees do.” And, I am here to tell you that it ain’t the same thing at all when you come to appreciate what the hand, biomechanically, is capable of doing and you look at the elaboration of complex human behavior; planning, thought, design, you driven to dig deeper and go further back. What you find when you go further back is that over millions of years subtle changes in the anatomy of the hand, the musculature of the hand, the joint structure of the hand created the possibility, mechanically, of manipulative acts that other animals—even the highest apes, the brightest chimps, Bonobo Chimps, the works, are not remotely capable of doing.

I was recently at a conference of cognitive psychologists in London, and I showed a video, just a very brief video of a chimpanzee being handed a small round object, about the size of a small walnut. The object goes into the hand; it rolls around in the hand and then it falls out. The chimp’s thumb is very small, and the fingers move parallel when they close into the hand. Now, they are very strong and they are very good moving in the up/down direction, but the animal is not capable of opposing the tips of the fingers, at all, to the thumb. Having shown that particular video, I showed the video of a nine or a ten-year-old kid, who is enrolled in a woodworking class at a school in Marin County. This is a school that tolerates the activities of a wonderful guy named Al Mayberry, who has been teaching carpentry to primary grade kids for over 25 years. [The students in] this sixth grade class were building dulcimers, and they were not out of kits. There is a long and fascinating story about this, but the point of the story here is that I showed a video clip to these psychologists in London, who are all eminent theoreticians. Here is the chimp trying to manage a little, round, irregular object rolling around in the hand, which it simply cannot hold, and here is a nine or a ten-year-old kid, who is stringing a dulcimer that he has just built, and the gasps in this audience were very refreshing to me to hear because it was clear that they hadn’t made the connection that this is from another planet, this kind of behavior. For me, now, the challenge has been and continues to be, first of all, to convince people that it isn’t a trivial matter that our hand and thumb are different and are capable of high-level skill. But the period of time . . . What is really important is helping people understand that all of the things that we associate with high-level human cognition can be traced to a long period of time during which the demand on the body and the mind for survival in a relatively small and otherwise defenseless animal really came depend upon what it was able to do with its hands in an environment that was full of predators.