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.