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Phineas Gage and the Prefrontal CortexAs we traverse millennia and continents from ancient Taoist sages to modern scientific researchers, we need to make a brief but important pit stop—in the unlikely location of the state of Vermont in the summer of 1848.
That summer, an athletic and popular young man named Phineas Gage was working as a construction foreman for the Rutland & Burlington Railroad company. One afternoon, he was leading a crew laying explosives in outcroppings of rock to prepare the ground for new railroad track, when disaster struck. A moment of distraction led to an unexpected explosion that caused a metal rod to pass right through the front of Gage’s head. Amazingly, Gage survived the accident. Thanks to his robust health, and the attentive care of his physician, he was pronounced cured within two months. However, although he regained his physical health, Phineas Gage had become a different person, and the cause of his extreme change in personality would make him a legend in the history of neuroscience. The pleasant and urbane person who had been so popular with both his fellow workers and his bosses was no more. Instead, as Gage returned to health, in the concerned words of his physician, he was now “fitful, irreverent, indulging at times in the grossest profanity which was not previously his custom, manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, . . . devising many plans of future operation, which are no sooner arranged than they are abandoned.” His language was so foul that women were advised not to remain in his presence for long. His friends noted sadly that “Gage was no longer Gage” and his employers wouldn’t take him back. As his life unraveled, Gage spent years as an itinerant farmhand, before finding a new role as a circus attraction, displaying the tamping iron that had caused the hole in his head. Left: A daguerreotype portrait of brain-injury survivor Phineas P. Gage, holding the tamping iron which injured him. Right: Gage's skull on display at Harvard Medical School.
COLLECTION OF JACK AND BEVERLY WILGUS / WIKIMEDIA COMMONS What had happened to him? Modern neuroscience can now explain that Gage’s accident had destroyed large portions of his prefrontal cortex (PFC), the part of the brain responsible for what is called the executive function. The PFC allows us to think and act in ways that other animals don’t. It controls our basic physiological drives and enables us to plan, conceptualize, and make abstract rules. It permits us to think symbolically—a prerequisite of the human language faculty. In fact, there is a striking convergence between the capabilities mediated by the PFC and the type of “knowing” that the Taoists believed separated humans from the Tao. Could the evolution of the PFC in humans have been responsible for the emergence of what the Taoists called yu-wei—for purposive, goal-oriented thinking?
When the original Taoists identified a certain kind of human cognition that was responsible for language, for goal orientation, and for the artifice of civilization, they likely had in mind the kind of conceptual thinking that is mediated by the PFC. For the Taoists, this type of thinking was responsible for the loss of wu-wei, the harmonious way of being that allowed one to flow effortlessly through life. But when Phineas Gage had the misfortune to damage a large part of his PFC, his life unraveled. He certainly didn’t enjoy a harmonious existence. What accounts then, for the difference between the Taoist view and Gage’s experience? Can they be reconciled? In order to answer this, we need to get a better sense of how our executive suite functions. And in doing so, we will begin to uncover some core insights into the human experience that will help launch our journey through the rest of this book. Excerpted from The Web of Meaning, Chapter 1, "The Nameless Uncarved Wood" |