In a special Big Think conversation arranged by Discover magazine and published online today, Dr. Antonio Damasio, a behavioral neurobiologist at the University of Southern California speaks with novelist Siri Hustvedt about various topics in neurology, from how the brain arranges our consciousness and coordination, to how it constructs our memories and processes emotion.
"The process of consciousness is the process that allows us to run our lives personally and in society the way we do," says Damasio to Hustvedt. "It’s the thing that gives us access to high thinking and high decision making and very high qualities of reasoning."
One of the major topics the two discuss is whether there is a biological basis for believing that humans have free will. Hustvedt wonders whether free will has to be a fully conscious action, saying: "If you’re thirsty and you get a glass of water you don’t necessarily have full, subjective linguistic consciousness of getting a glass of water, right, so but also I think you might want to refine this notion of the degree to which a finding like that does not tell us that we have no free will." According to Damasio: "We do have a measure of control, but it is not true that we have full control and it is not true that when we are executing an action we are necessarily controlling it at that moment consciously."
They also spoke about the mechanisms by which the brain records a memory, one of Damasio's major fields of study. Damasio explained his concept of convergence/divergence zones, where the brain stores bits and pieces of individual memories in various parts of the brain. What we know as a specific memory is a reconstruction of a moment in a convergence zone—"a sort of internal testimony of the simultaneous occurrence of certain things at a certain point," says Damasio. This allows the brain to have a certain economy, remembering things that are necessary and stringing particular details together when necessary—but not remembering an entire "filmic" representation of a scene verbatim. This is what accounts of lapses in memory and mistaken memories.
One factor that can make memories less accurate is emotion. When a memory is filtered through a particularly intense emotional experience, it can be distorted and altered in major ways. Damasio and Hustvedt talked about how emotions affect memory, and also about how study of the neurology behind emotion evolved out of behaviorism. Over time, scientists were able to understand human emotion by studying people whose brains had been damaged or otherwise impaired in specific ways. The classic example of this is the odd case of Phineas Gage, a young railroad foreman in the mid-19th Century who lost his ability to feel emotions after a railroad spike was driven into a specific part of his brain.
Thanks to Discover for arranging the discussion between Damasio and Hustvedt. An edited transcript of their discussion can be found in the October, 2010, issue of Discover magazine.