Descartes' Error

"This is also a book – like most of the books I have chosen are – on the distinction between subterranean mental processes and conscious processes. And Damasio’s work concerns emotion and the role of emotion in decision-making. We have an idea that every day decisions are shaped by rational thinking, Dr Spock-type logical thinking. But Damasio worked with people who have suffered strokes and as a result are incapable of feeling emotion. And far from making good decisions, they make terrible decisions, and their lives fall apart. His theory, which has now been widely accepted, is called the somatic marker hypothesis. So the basic idea is that emotions is how we value things, it’s our GPS system. When we see something as trivial as an ice-cream cone or as important as a potential spouse, our emotions say we either want that or we don’t, it’s going to lead to pleasure or to pain. And we follow that emotional signal. So the error Descartes made was to separate the mind and the body; the idea that the mind can exist without the visceral emotional reactions of the body. Because you actually can’t have a brain thinking without those visceral reactions. The application for me is that it gives me a new view of how human beings make decisions and operate. We believe that people make decisions based on rational and clear responses to incentives. But in case after case they don’t make decisions that way. And I think most of us understand that the economic model of human nature is not really accurate. And yet all our public policies are based on that model. Economists have tremendous sway over public policy, over foreign affairs. Game theorists impact on our international relations people, they train our public policy figures. And for me, as a result of these books, I just observe and place a lot more emphasis on unconscious decision-making. I’m interested in cultural influences that shape our behaviour in ways that we don’t understand, and even the way that genetics can shape our behaviours in ways that we don’t understand."

"The first is that he puts a big stress on the importance of emotions to rationality. People often think that rationality and emotions are in conflict with each other. You hear people say ‘Stop being emotional, be rational.’ What I learned from Damasio is that that is just not a good way of looking at it. By drawing on famous examples, such as Phineas Gage, and by drawing on his really deep knowledge of neuroscience, he shows ways in which rationality, especially the kind of rationality that is involved in decision-making, really does require having your emotions working well. The second respect in which this was a breakthrough book is the way in which it understood emotion in terms of what the brain does – not as a kind of abstract computational process (the way a lot of ideas at the time about thinking worked) but very much tied in with the particular brain processes. So the insights are: firstly, emotions matter to thinking about how you should live your life, and, secondly, the brain matters to thinking about emotions. So if you put those two things together, you get a different approach to thinking about the meaning of life: one which takes emotion seriously, and the other which takes the nature of the brain seriously. A starting point for a lot of Damasio’s research was the 19th century case of Phineas Gage. He was a railroad worker who took a rod through his head, and it should have killed him, but he survived, despite the fact he clearly had a hole in his head. What’s really interesting is that his personality changed. He retained his ability to use words articulately, and he was certainly OK doing mathematics. But, basically, he became a jerk. He went from being a responsible employee and a good family person to being someone who was very difficult to get along with. So the brain damage he got didn’t affect his reasoning ability, but it really affected his behaviour in negative ways. What Damasio discovered, using the old pictures of where Phineas Gage had gotten the rod through his head, is that it had damaged a part of his brain that was very important for connecting high-level reasoning with the emotions. Then Damasio, who is a neurologist, was able to find similar kinds of damage in a bunch of patients that he was treating in Iowa at the time. So this was a way of getting at how crucial the interconnections between verbal and mathematical reasoning on the one hand, and emotional processes on the other, are to enabling people to function well as human beings. And that becomes really crucial for assessing what it is to find a meaningful life. It isn’t just a matter of being able to reason about how you should live your life; it’s a question of getting your emotions engaged in a way that makes your brain work, to enable you to find meaning in life."