The tumor that erased Tom's memory did not touch his "soul."
Tom was one of those people we all have in our lives -- someone to go out to lunch with in a large group, but not someone I ever spent time with one-on-one. We had some classes together in college and even worked in the same cognitive psychology lab for a while. But I didn't really know him. Even so, when I heard that he had brain cancer that would kill him in four months, it stopped me cold.
I was 19 when I first saw him -- in a class taught by a famous neuropsychologist, Karl Pribram. I'd see Tom at the coffee house, the library, and around campus. He seemed perennially enthusiastic, and had an exaggerated way of moving that made him seem unusually focused. I found it uncomfortable to make eye contact with him, not because he seemed threatening, but because his gaze was so intense.
"Please forgive me for asking this, but I do this with everybody. Could you tell me your name again and how it is that I know you?"
Once Tom and I were sitting next to each other when Pribram told the class about a colleague of his who had just died a few days earlier. Pribram paused to look out over the classroom and told us that his colleague had been one of the greatest neuropsychologists of all time. Pribram then lowered his head and stared at the floor for such a long time I thought he might have discovered something there. Without lifting his head, he told us that his colleague had been a close friend, and had telephoned a month earlier to say he had just been diagnosed with a brain tumor growing in his temporal lobe. The doctors said that he would gradually lose his memory -- not his ability to form new memories, but his ability to retrieve old ones ... in short, to understand who he was.
Tom's hand shot up. To my amazement, he suggested that Pribram was overstating the connection between temporal-lobe memory and overall identity. Temporal lobe or not, you still like the same things, Tom argued -- your sensory systems aren't affected. If you're patient and kind, or a jerk, he said, such personality traits aren't governed by the temporal lobes.
Pribram was unruffled. Many of us don't realize the connection between memory and self, he explained. Who you are is the sum total of all that you've experienced. Where you went to school, who your friends were, all the things you've done or -- just as importantly -- all the things you've always hoped to do. Whether you prefer chocolate ice cream or vanilla, action movies or comedies, is part of the story, but the ability to know those preferences through accumulated memory is what defines you as a person. This seemed right to me. I'm not just someone who likes chocolate ice cream, I'm someone who knows, who remembers that I like chocolate ice cream. And I remember my favorite places to eat it, and the people I've eaten it with.
Pribram walked up to the lectern and gripped it with both hands. When they had spoken last, his colleague seemed more sad than frightened. He was worried about the loss of self more than the loss of memory. He'd still have his intelligence, the doctors said, but no memories. "What good is one without the other?" his colleague had asked. That was the last time Pribram spoke to him.
From a friend, Pribram had learned that his colleague had decided to go to the Caribbean for a vacation with his wife. One day he just walked out into the ocean and never came back. He couldn't swim; he must have gone out with the intention of not coming back -- before the damage from the tumor could take hold, Pribram said.
The room was silent for 10 or 15 seconds -- stone silent. I looked over at Tom's notebook. "Neuropsychologist contemplates losing his mind," Tom had written.
If he had lived, Pribram's colleague would have experienced what neuroscientists call retrograde amnesia. This is the kind of amnesia that is most often dredged up as a plot element in bad comedies and cheap mystery stories; so-and-so gets hit on the head and then can't remember who he is anymore, wanders around aimlessly, finding himself in zany predicaments, until he gets hit on the head again and his memory remarkably returns. This almost never occurs in real life. Although retrograde amnesia is real, it's usually the result of a tumor, stroke, or other organic brain trauma. It isn't restored by a knock on the head. Because they can still form new memories, patients with retrograde amnesia are acutely aware that they have a cognitive deficit, are painfully knowledgeable about what they are losing.
Tom and I crossed paths years again later when we were both working for a research company. He was part of a team designing virtual musical instruments for non-musicians, like Guitar Hero or Rock Band, seeking to give customers an awesome music-playing experience after zero hours of practice. I saw Tom in the halls from time to time, said hello, saw him at a couple of company jam sessions; he was a really good keyboard player.
Sometime after I left the research company to begin my first academic job, I ran into a woman from the company who asked if I'd heard the news about Tom.