The Phineas Gage Story
A Daguerreotype of Phineas Gage, After His Recovery from the Accident
In 1994, I was fascinated by Antonio Damasio's account of how Phineas Gage had an iron bar blown through his brain, and how the damage to one region of his brain--the ventromedial prefrontal cortex (vmPFC)--turned him into something like a psychopath with no moral sense, showing the same changes in moral personality that Damasio had seen in his patients with damage to the frontal lobes of the brain. These patients had suffered no decline in their intellectual capacities for speaking and abstract reasoning, but they lacked the capacity for practical reasoning about how to act in socially appropriate and personally advantageous ways, because they lacked the moral emotions to motivate them in planning their lives. What this showed was that there was no sharp separation between reason and emotion, because emotion was part of good practical reasoning (Damasio et al. 1994; Damasio 1994).
Damasio's work had a crucial influence on my writing of Darwinian Natural Right in 1998, in which I argued that the biological ethics of human nature required a complex interaction of reason and emotion, which confirmed the rational emotivism of Aristotle, David Hume, and Adam Smith, and refuted the rationalist ethics of Immanuel Kant. (I have written about Damasio's Spinozist neuroscience here and here.)
But then sometime around 2002, I read Malcolm Macmillan's An Odd Kind of Fame: Stories of Phineas Gage, and I was persuaded by him that Damasio's account of Gage was distorted by Damasio's failure to see that Gage's mental and moral decline was only temporary. In recent weeks, I have been thinking more about this, and now I see that Damasio was at least partially correct about what Gage teaches us, although Damasio was mistaken in assuming that the damage to Gage was permanent and irreversible. The plasticity of the brain allows for some limited recovery even from brain injuries as severe as that suffered by Gage. Moreover, recent research in the neuroscience of morality suggests that while the brain does support moral judgment, there is no specifically moral center of the brain, but there is a complex neural network of brain regions that sustains moral experience.
On September 13, 1848, Gage was 25 years old, and he was the foreman over a work crew working for the Rutland and Burlington Railroad south of Cavendish, Vermont. Their job was to prepare a flat roadbed for laying track by blasting through the rocky hills. To do that, they had to bore deep holes in the rock, put blasting powder and a fuse in the hole, and then add sand and clay in the hole so that the blast's energy would be directed into the rock. Gage had to use a tamping rod to pack the sand and clay. He had had a blacksmith make a special rod for him that was three feet seven inches long, 1 and 1/4 inches in diameter, and weighing over 13 pounds. The end of the rod entering the hole was tapered down to a point 1/4 inch in diameter.
He was working on a hole filled with powder and a fuse. He was distracted by something he heard from his men, and he turned his head over his right shoulder to speak to them. At that point, he dropped his rod into the hole, and the rod rubbing against the rock created a spark that ignited the powder. The explosion launched the rod like a missile, entering the left side of Gage's face, passing behind his left eye, into the left side of his brain, exiting the top of the skull through the frontal bone, then passing out of his brain and landing some 80 feet away smeared with blood and brain.
Gage was thrown onto his back. But, amazingly, within a few minutes, Gage was speaking and walking around. He was taken into town where two doctors--Edward Williams and John Harlow--treated him. Harlow took charge of the case and cared for him over the next six months. Harlow kept notes on the case, and most of what we know about Gage comes from Harlow's published reports about Gage in1848 and 1868. A few other doctors--particularly Henry Bigelow, professor of surgery at Harvard University--also saw Gage and wrote about him.
Harlow concluded that the damage to Gage's brain had been primarily to the anterior and middle lobes of the left cerebral cortex, so that whatever function that part of the brain served must have been destroyed. Apparently, this lost function had something to do with moral personality, because that was the change that Gage showed. In his 1868 report, Harlow wrote:
". . . His contractors, who regarded him as the most efficient and capable foreman in their employ previous to his injury, considered the change in his mind so marked that they could not give him his place again. The equilibrium or balance, so to speak, between his intellectual faculties and animal propensities seems to have been destroyed. he is 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 in turn for others appearing more feasible. A child in his intellectual capacity and manifestations, he has the animal passions of a strong man. Previous to his injury, though untrained in the schools, he possessed a well-balanced mind, and was looked upon by those who knew him as a shrewd, smart business man, very energetic and persistent in executing all his plans of operation. In this regard, his mind was radically changed, so decidedly that his friends and acquaintances said he was 'no longer Gage'" (reprinted in Macmillan 2000, 414-15).
These brief comments by Harlow were responsible for making Gage's story the most famous case of brain injury--often mentioned in textbooks of psychology and neurology, along with pictures of Gage's skull--because this seemed to show that human personality--the human soul or spirit--is a biological product of particular areas of the human brain that can be lost when the brain is damaged: Gage was no longer Gage.
From Gage's mother, Harlow learned about Gage's subsequent life. He travelled around New England exhibiting himself, along with his tamping iron, to audiences who paid to see him. In New York City, he was an exhibit at P. T. Barnum's Museum. Then, in 1851, he worked in a livery stable in Hanover, New Hampshire, for a year and a half. In August, 1852, he was hired by a businessman who was setting up a line of coaches in Chile at Valparaiso; and Gage worked in caring for the horses and driving a coach between Valparaiso and Santiago for seven years.
Then, in 1859, Gage became ill, and he decided to leave Chile and travel to San Francisco to live with his mother who had moved there. Gage worked briefly for a farmer in Santa Clara. But he began to have severe epileptic convulsions that killed him in 1860.
For some years, Harlow had lost track of Gage until he began to write to Gage's mother in 1866. She reported how he had died. At Harlow's request, she and her family agreed to exhume Gage's body and detach his skull so that they could deliver it to Harlow for scientific study. Harlow arranged to have the skull and Gage's tamping iron given to the Harvard Medical School, where they became the most famous items in the school's museum.
In 1994, Damasio and his colleagues took measurements from Gage's skull at Harvard and used modern neuroimaging techniques to reconstruct the probable path of the rod through Gage's brain and thus determine the exact location of the damage. They inferred that the ventral and medial sectors of both left and right prefrontal cortices were damaged. So the damage was not limited to the left side as Harlow had said.
Damasio had seen the same damage in some of his patients at the University of Iowa Hospitals, who displayed the same personality changes shown by Gage. Like Gage, there was no decline in their general intelligence, memory, or learning; but they had lost their capacity for planning and executing good moral decisions. This suggested that the ventromedial prefrontal cortex was the one region of the brain crucial for moral judgment. Damage to this part of the brain seem to cause what Damasio called "acquired sociopathy," because those with such brain lesions behaved like sociopaths or psychopaths, who lacked any conscience or moral sense. They understood intellectually the difference between good and bad conduct, but they lacked the emotional motivation to choose the good. They were condemned, Damasio observed, "to know but not to feel" what they ought to do.
But was this really true for Gage? Damasio claimed that before the accident Gage had been "a responsible, intelligent, and socially well-adapted individual, a favorite with peers and elders." Then, after the accident, he suffered "profound change in personality"--"Gage was no longer Gage": "he had become irreverent and capricious. His respect for the social conventions by which he once abided had vanished. His abundant profanity offended those around him. Perhaps most troubling, he had taken leave of his sense of responsibility." As a consequence, "Gage never returned to a fully independent existence, never again held a job comparable to the one he once had" (Damasio et al. 1994, 1102).
Against Damasio, however, Macmillan argues that the moral degeneration in Gage after the accident was only temporary, and that he did show at least a partial recovery. The evidence for this is that he did eventually support himself with some steady jobs. He worked at the livery stable for a year and a half, and he worked as a coach driver in Chile for seven years. Being a successful coach driver on the route between Valparaiso and Santiago would have required practical and social skills in satisfying the needs of his passengers. A few years ago, Macmillan found evidence that in 1860 a Dr. Henry Trevitt, who had lived in Valparaiso, reported "that he knew Gage well; that he lived in Chile, where he was in stage driving; and that he was in the enjoyment of good health, with no impairment whatever of his mental faculties" (Macmillan and Lena 2010, 648).
Neuroscientists today often identify the frontal lobes as serving the "executive functions" of the brain in providing a central supervisory system that organizes practical decision-making, so that damage to the frontal lobes produces a "dysexecutive syndrome" in which people cannot organize their practical lives in a rational manner--their behavior becomes erratic and impulsive. As Macmillan observes, rehabilitation programs for people who have suffered severe frontal lobe damage often try to restore some of this executive management by providing a tight routine of external structure that teaches the patients to organize their thoughts and actions through a daily repetition of a step-by-step process to achieve specific goals.
Macmillan thinks Gage's job as a stagecoach driver in Chile provided him an informal version of this rehabilitation program. Macmillan has found some newspaper reports of the daily coach run between Santiago and Valparaiso--leaving Valparaiso at 4 a.m. for a 100-mile, 12-13 hour journey to Santiago. We can imagine that Gage would have had to rise well before 4 a.m. to feed, groom, and harness the horses. He would then have had to load the passengers' luggage, collect their fares, and then provide for their needs throughout the day, while skillfully driving the horses over rugged and crowded roads. Thus, his daily work was organized by a strict external structure. And he must have been good at this if he was employed in this for seven years, perhaps by the same employer (Macmillan and Lena 2010, 645).
Macmillan recognizes this as the kind of rehabilitation that was developed by Aleksandr Romanovich Luria, a famous Soviet neurologist, for the rehabilitation of Red Army soldiers with frontal lobe brain injuries from World War II. Luria believed that the frontal lobes of the brain allow us to use an internal language to plan and regulate our actions to achieve our goals: we talk ourselves through our day. Patients with damage to the frontal lobes must learn how to do this. Luria would have supervisors talk to their patients, telling them what to do step-by-step to achieve some simple goal. Then the patients would be told to repeat these words to themselves as they moved through each step of the task. This would be done over and over every day in exactly the same way, until finally the patients would develop a simple internal language of supervising their own behavior so that their lives would become highly structured. Luria admitted, however, that complete success--particularly with massive frontal damage in both lobes--was almost never achieved. Very few of his patients learned to live independently (Luria 1980, 246-365).
Macmillan sees a similar kind of rehabilitation program in some reports of how people with severe frontal lobe damage can learn to control their conduct when they are habituated by structured environments of behavioral conditioning. For example, Thomsen, Waldemar, and Thomsen (1990) have related the 20-year case history of a young woman who at age 17 was involved in a car accident that killed both of her parents and left her with bilateral frontal lobe damage. She regressed to a state of extreme childishness with grasping, sucking, and yawning movements. She showed almost no emotion, and she could not establish any emotional contact with anyone. She could not care for herself, and so she had to live in nursing homes for over 10 years. Before the injury, she had completed 9 years of schooling, and she had had good relationships with her schoolmates and her teachers. She had normal intelligence. But those who knew her thought she was rather immature.
13 years after her injury, she was 30 years old, and she began living with a 45-year-old man, who cared for her, and without having any sexual relationship with her. He patiently wrote out a program for how she should do the housework, which he read to her every day in exactly the same words. He praised her when she did something well. After a full year of this, she showed no improvement. But by the second year, he had some success, in that she did the housework and the shopping without his assistance. She was no longer restless. She spoke kindly about her partner and his family. But she remained childish in her mind and character.
Just like Luria's patients, people like this woman with massive frontal lobe damage can show some improvement in managing their life when they are guided by a strict program of behavioral conditioning, but the success is very limited, and they never recover the normal moral judgment that they had before their brain injury.
To me, that confirms Damasio's conclusion about people like Gage--that without the normal functioning of the ventromedial prefrontal lobes, human beings lose their capacity for good moral character. Even Macmillan seems to concede that when he writes:
"Phineas Gage made a surprisingly good psycho-social adaptation: he worked and supported himself throughout his post-accident life; his work as a stagecoach driver was in a highly structured environment in which clear sequences of tasks were required of him; within that environment contingencies requiring foresight and planning arose daily; and medical evidence points to his being mentally unimpaired not later than the last years of his life. Although that Phineas may not have been the Gage he once had been, he seems to have come much closer to being so than is commonly believe" (Macmillan and Lena 2010, 655).
"Phineas may not have been the Gage he once had been." So Gage was no longer Gage?
I assume, however, that Macmillan would want to insist that Damasio is still wrong in claiming--like the phrenologists--that moral judgment resides in one specific part of the brain. Now Damasio does indicate his partial agreement with the phrenologists of the 19th century. He agrees with Franz Joseph Gall's claim that the brain is the organ of the spirit. He also agrees with the phrenologists in that "brain specialization is now a well-confirmed fact." But he disagrees with the claim that each function of the brain depends on a single "center" that is independent of the other parts of the brain. Instead of that, he sees that each mental function--such as vision, language, or morality--arises from systems of interconnected brain regions. So while the ventromedial prefrontal cortices are important, perhaps even necessary, for moral judgment, the execution of this function depends on a collection of systems in which many parts of the brain must be properly connected (Damasio 1994, 14-17, 70-73). So Sandra Blakeslee (1994) was mistaken in her article on Damasio's research when she said that he had identified the "brain's moral center."
I will develop this point--that morality depends on the complex interaction of many different parts of the brain--in my next post.
REFERENCES
Blakeslee, Sandra. 1994. "Old Accident Points to Brain's Moral Center." New York Times, May 24.
Damasio, Antonio. 1994. Descartes' Error: Emotion, Reason, and the Human Brain. New York: G. P. Putnam's Sons.
Damasio, Hanna, Thomas Grabowski, Randall Frank, Albert Galaburda, and Antonio Damasio. 1994. "The Return of Phineas Gage: Clues About the Brain from the Skull of a Famous Patient." Science 264: 1102-1105.
Luria, Aleksandr Romanovich. 1980. Higher Cortical Functions in Man. Second Edition. Trans. Basil Haigh. New York: Basic Books.
Macmillan, Malcolm. 2000. An Odd Kind of Fame: Stories of Phineas Gage. Cambridge: MIT Press.
Macmillan, Malcolm, and Matthew Lena. 2010. "Rehabilitating Phineas Gage." Neuropsychological Rehabilitation. 20: 641-658.
Thomsen, Inger Vibeke, Gunhild Waldemar, and Anne Marie Thomsen. 1990. "Late Psychosocial Improvement in a Case of Severe Head Injury with Bilateral Fronto-Orbital Lesions." Neuropsychology 4: 1-11.
No comments:
Post a Comment