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No. 929:
Gage's Brain

Today, an old accident raises new questions about morality. 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.

In 1848, Phineas Gage, a 25-year-old railway foreman, tamped down a dynamite charge. He was trying to level a rail bed in the rocky soil of Vermont. He used a 3½-foot tamping rod, 1.2 inches in diameter. The unstable powder went off.

And so, on that September day a century and a half ago, Gage's tamping rod shot back into his face like a long artillery shell. It entered under his left cheek, drove upward taking out his left eye, passed through the frontal lobes of his brain, out the top of his skull, and on up into the autumn sky.

The wreckage of Phineas Gage fell to the ground. But his wreckage shook off the shock. He talked to his men as they helped him walk away. The wound healed, and he lived another 13 years.

Yet you might wonder if it was really Gage who survived that terrible accident. He'd been bright, efficient, and responsible. After the explosion, his intelligence and memory were intact. He'd lost an eye but otherwise seemed to've recovered completely.

But he'd changed. He'd lost his social constraints. He became an unreliable liar. His language grew coarse. He never held a responsible position again.

A few years after Gage's death, his doctor, John Harlow, got permission to dig up the remains. The tamping rod had been buried with him. Harlow preserved it along with the skull it had so savaged. He studied the wound. Then he suggested that a part of the brain serves to plan and execute "suitable" behavior.

No one had autopsied Gage, and Harlow had only his skull. He couldn't pinpoint which parts of the brain had been torn away. Victorians believed in brain centers for motion and language. But one for ethics and judgment? They called Harlow a crank.

Now Drs. Hanna and Antonio Damasio have put a 3-D replica of Gage's skull in the computer along with a 3-D replica of a normal brain that would've fit Gage's skull. They replay the accident in virtual reality. They can see just what part of Gage's brain was excised; and they know what Gage became when it was gone.

They combine that with other people's frontal brain injuries. In the end they support Harlow's suggestion. Damage to the left and right prefrontal cortices, they say, results in defective rational decision making and poor processing of emotions.

So newspapers claim that science has found a "moral center" in our minds. I doubt it. Gage's tamping rod tore away the skill of social control. Both the moral and the immoral among us use that skill! The Damasios aren't talking about morality. What they really show us is that an old accident has much to tell us when we have the wits to read it with 20th-century tools.

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

(Theme music)

Damasio, H., Grabowski, T., Randall, F., Galaburda, A.M., and Damasio, A.R., The Return of Phineas Gage: Clues About the Brain from the Skull of a Famous Patient, Science, Vol. 264, May 20, 1994, pp. 1102-1105 and Cover.

Blakeslee, S., Old Accident Points to Brain's Moral Center, Science Times, The New York Times, Tuesday, May 24, 1994, pp. B5 and B8.

For more on Phineas Gage, click here.