Free Will: Fact or Fiction

[Angrboda]

The Strange Case of Phineas Gage

The strange story of Phineas Gage is one of the classic cases of neurology, and one of the first that led scientists to suspect that there might be regions of the brain specifically devoted to personality and reasoning. The terrible accident this man suffered, while tragic, also served to cast a gleam of light on the inner workings of the mind and reveal how fragile the neurological construct called the self is in all of us.

It was the summer of 1848, in New England, and the Rutland and Burlington Railroad Company was building new tracks for its trains. The proposed path ran over uneven ground, and outcrops of stone had to be blasted to clear a way for the rails to be laid.

The construction crew supervising the blasting was led by one Phineas Gage, a 25-year-old man whose employers described him as "the most efficient and capable foreman in their employ" (Macmillan 2000, p. 65). He was further said to have "temperate habits" and "considerable energy of character", and "was looked upon by those who knew him as a shrewd, smart businessman, very energetic and persistent in executing all his plans of action" (ibid.) In short, a better person to lead the construction crew could not have been found.

In order to blast, the crew would drill a narrow shaft in the rock, fill it halfway with explosive powder, insert the fuse, and then fill the hole the rest of the way with sand, which would direct the explosion inward, toward the rock it was intended to destroy. Once the sand was added, it had to be tamped down with an iron bar, then the fuse was lit and the blast went off. Gage and his crew were performing just such a procedure when the fatal mistake occurred.

For one particular shaft, the blasting powder had been poured and the fuse set, but the sand had not yet been poured. However, before it could be added, Gage became distracted and unthinkingly tamped down the explosive powder itself. His iron tamping rod struck sparks, the powder ignited, and the blast - channeled and directed by the narrow walls of the drill shaft - went off in Phineas Gage's face. The tamping iron, which had been in the hole at the time, was propelled upward like a bullet straight at his head.

The iron tamping rod, over three feet in length and tapering from an inch-and-a-quarter diameter at one end to a quarter-inch at the other, pierced Gage's left cheek point first, penetrated the base of his skull, passed through the front of his brain, and flew out through the top of his head, leaving a ghastly exit wound. Covered with blood and brain material, the iron landed over a hundred feet away. Gage was knocked over by the force of the blow, but astonishingly, then sat up and spoke. He was conscious and seemed in command of his faculties, despite the terrible injury he had suffered. His men helped him get to town to see a doctor.

The physician who examined him, Dr. John Harlow, confirmed that initial impression. Phineas Gage was fully coherent; he was not paralyzed and had no difficulty walking, speaking or using his hands. He had lost sight in his left eye as the result of his accident, but otherwise his senses and faculties were intact. He even spoke with Harlow perfectly calmly and rationally despite the gaping wound in his skull. In disbelief, the doctor helped treat him, and with his help Gage eventually survived the injury and a subsequent infection and fever - a major achievement by itself, in an age before antibiotics.

However, it soon became apparent that Gage had not survived his ordeal unchanged. Almost immediately after his fever had passed and his wounds had healed, major and surprising changes in his personality began to surface. In essence, he was no longer the man he had been before the accident. As Dr. Antonio Damasio writes:

"Yet this astonishing outcome [Gage's survival] pales in comparison with the extraordinary turn that Gage's personality is about to undergo. Gage's disposition, his likes and dislikes, his dreams and aspirations are all to change. Gage's body may be alive and well, but there is a new spirit animating it." (Damasio 1994, p. 7)

The man Phineas Gage had been before his accident was gone. As a perplexed Dr. John Harlow wrote, he had become "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, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged than they are abandoned... A child in his intellectual capacity and manifestations, he has the animal passions of a strong man." (quoted in Damasio 1994, p. 8)

A sharper contrast with the man he had been before would be impossible to imagine - "the alterations in Gage's personality were not subtle" (p. 11). Where once he had been polite, modest and likable, he had become crude, profane and tactless. Where once he had been responsible and goal-driven, he now became lazy and irresponsible, and would conceive all kinds of wild plans and fail to follow up on any of them. Where once he had made shrewd and wise decisions, it now seemed he was actively attempting to drive himself to ruin through repeated instances of bad judgment. So dramatic and obvious was the change that his former friends sadly said that he was "no longer Gage" (quoted in Damasio 1994, p. 8). His employers refused to give him his old job back, not because he lacked the skill, but because he no longer had the discipline or the character.

For the next several years, Gage held menial jobs working in a stable or as a stagecoach driver. However, in 1860, he began unexpectedly suffering from seizures. After this, his decline began to accelerate; he worked as a farmhand and did other odd jobs, but always moved on before long, as he "[found] something that did not suit him in every place he tried" (Macmillan 2000, p. 66). Finally, on May 21, 1861, he suffered a series of major seizures, slipped into a coma, and died without regaining consciousness.

Gage's skull was exhumed after his death and became a museum exhibit, and a hundred and twenty years later, Dr. Damasio and his colleagues decided to analyze it to determine exactly where his brain had been injured. Building up a three-dimensional computer model of his skull, they ran simulations to determine the most likely path of the iron bar through it based on the never-fully-healed entrance and exit wounds.

What they found was not surprising. The region of Gage's brain that was damaged was a part of the frontal lobes called the ventromedial prefrontal cortex - precisely the part now believed to be critical for normal decision-making (p. 32). With this part of his brain destroyed, he was unable to plan for the future, behave himself according to social rules and customs, or decide on the most advantageous course of action. That he behaved as he subsequently did was to be expected, and was not his fault or the result of any conscious decision. Dr. Damasio writes, "It is appropriate to say... that Gage's free will had been compromised" (p. 38).

The most important lesson that we can draw from the strange and tragic case of Phineas Gage is that the frontal regions of the brain play a major role in determining personality. Likewise, they play a crucial role in controlling behavior, allowing us to inhibit our reckless impulses and conduct ourselves as society expects. These functions can be disabled when the frontal lobes are damaged or destroyed. Nor is Phineas Gage's case the only one like it on record. As the remainder of this section will show, there are many more examples of people with frontal lobe damage who exhibit similar symptoms: an inability to make wise decisions, to behave as law or custom expect, and to fit into society as an ordinary human being. How can a dualist hypothesis explain this? Did the blast of the iron on that morning in 1848 knock Gage's soul out of his head? A materialist theory of mind can easily explain how a person's character traits can be altered by physical harm. For dualist models that hold that character traits ultimately arise from an immaterial "ghost" invulnerable to harm, these cases are not similarly explicable.

— Ebon Musings, The Atheism Pages: