Blogosophy

Descartes' Error

I'm finally getting around to blogging on Descartes' Error: Emotion, Reason, and the Human Brain, by Antonio Damasio. This is a fascinating attempt to pull together what's currently known about the neurophysiology of brain-function, including Damasio's own research into a coherent account of human's capacity for reason and the fundamental role that emotion plays in it. At the center of the book is research done on patients, in particular one patient called Elliot, who have had certain specific portions of their brains damaged (whether by accident or as a result of tumors) which prevent them from feeling emotion normally and how surprisingly this results in undermining their capacity for reason, despite all their logical facilities and capacity for abstract thought being completely unaffected. (I've mentioned this before in connection with Patricia Churchland's Brain-Wise, which relies on some of Damasio's experiments.)

The most telling experiment goes as follows: Subjects play a card game. They are given a certain amount of money to start, and are seated in front of four decks of cards. Each card will either pay them some money (e.g. +50$) or take some away (e.g. -10$). Each turn they turn over one card from any of the four decks, and follow the payout instructions. Unknown to them, the decks have different mixes of cards such that two of the decks have low rewards, but lower penalties, and two of the decks have high rewards but even higher penalties. The players aren't allowed to keep records of their draws. Some of the subjects are normal people, others are patients who have the problem described in the previous paragraph and are unable to generate emotions although their reasoning powers are intact.
Normal players experiment with drawing cards from the various decks, and eventually settle on drawing from the two "winning" (low pay/low risk) decks, and make money. The emotionless players like Elliot also start by drawing randomly, but keep drawing from the high-risk loser decks, and eventually lose all their starting money. They are given more money, and lose that. They know that they haven't done well (they are perfectly aware that they went bust and "borrowed" more money), but they don't change their style of play at all.
The kicker is that they then repeated the experiment, switching the decks around, and measuring the galvanic skin response of the subjects as they played. Not surprisingly, the emotionless players skin response was flat all the way through. On the other hand, the normal players began showing galvanic skin response indicative of nervousness or unease when reaching for cards from "bad" decks even before they began to alter their pattern of play away from those decks. The response gets stronger and stronger, and eventually they start to disfavor those decks. That is to say, during the course of play as they experiment with drawing cards from different decks, they have a visceral response indicating a weighing of the probabilities even before they are conscious of the difference or can articulate any theory.

Damasio argues, and I'd have to agree, that this is really strong evidence that emotions and feelings are an integral part of how we reason about the world. Without feelings and subconscious emotional processing of the situations we are confronted with, it appears to be impossible to arrive at correct logical prudential decisions. He suggests, and offers some further evidence for, a theory that part of what's happening is that we use visceral responses to prune decision trees to the point where we can consciously reason about them, and without these visceral calculations that are part and parcel of our emotions even highly devloped abstract reasoning facilities such as Elliot's are overwhelmed and rendered ineffective at coming to conclusions. After the experiment, Elliot was able to correctly analyze what was wrong with his play, but confessed that even so if he were presented with the same situation again, he just wouldn't know what to do.