Today, a madonna makes tools. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Neurobiologist William Calvin wonders if women were among the prehistoric technologists. He does some inspired detective work to find out. He begins with mothers and babies.

The parent/child bond is powerful. House cats who know that climb in your lap to purr. Outdoor cats don't. Cats who live with humans learn to mimic babies. They lay a powerful claim to our affections. Nestling near the heart awakens a bond.

The heart's in the center of the chest, but the left ventricle pulses loudest. A baby is happier on its mother's left arm, where it takes the greatest comfort from her beating heart.

Maybe that's why most of us are right-handed. A mother survived with a child on her left arm if she could protect herself with the right. Calvin gives us the term, "The Throwing Madonna." That's the mother who can throw a stone at a jackal while she holds her child.

Now what has this to do with technology? Calvin points out that for right-handedness to have much Darwinian value, prehistoric mothers had to be deeply involved in the manual skills of survival. They had to be hunters, tool-makers, and tool users.

We can't go and look at cavemen, but we can look at advanced apes. Sure enough, hunting is shared among male and female apes.

So what about invention? Here's a case history: Primate biologists have studied Japanese macaque monkeys. In one test, the scientists scattered grain in the sand along a seashore. The monkeys needed to get at the grain.

One female monkey made a remarkable mental leap. She was trying to separate grain from sand. In frustration, she flung a handful into the sea. The sand sank. Grain floated back to her.

In no time, she'd formalized the procedure. The young apes were quickest to copy her. Some adult males never caught on.

Calvin goes further. African chimpanzees shape sticks to catch termites in anthills for supper. Females are far more creative and persistent at this technology. The same is true in selecting tools and inventing methods for cracking nuts. Why?

He offers a compelling hypothesis. Maybe it's because the female of the species spends more time with the young. And the young teach creative freedom of the mind to the old.

Much of this is speculative, but it all has the ring of truth in my ears. Calvin's imagery of "The Throwing Madonna" convincingly ties the bond between mother and child to the creative process. And we are reminded: It is in relinquishing the security of adulthood -- that we regain the creative muse.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Calvin, W.H., The Throwing Madonna: Essays on the Brain. New York: McGraw-Hill Book Co., 1983, Part I, Ethology and Evolution.

I am grateful to Laura Douglas, Gammage's Bookstore, Houston, for drawing my attention to Calvin's book and to his argument.