Back in 1994, Massimo Piattelli-Palmarini, Director of the Institute of San Raffaele in Milan, Italy, wrote a charming little book about common cognitive distortions called Inevitable Illusions. It is probably the very first comprehensive summary of behavioral economics intended for general audience. In it, he predicted that the two psychologists behind behavioral economics - Amos Tversky and Daniel Kahneman - would win the Nobel prize. I didn't disagree with the sentiment, but wondered how in the world were they going to get it since these two were psychologists and there is no Nobel prize in psychology. I didn't think there was much chance of them winning the Nobel Prize in economics. I was wrong and Piattelli-Palmarini was right. Kahneman won the Nobel prize in Economic Sciences. (Tversky unfortunately prematurely passed away by this time.) Just as Steve Jobs who was not in the music industry revolutionized it, the non-economists Kahneman and Tversky have revolutionized economic thinking. I have known Kahneman's work for quite some time and was quite excited to see that he was coming out with a non-technical version of his research. My expectations for the book were high and I wasn't disappointed.
Since other reviewers have given an excellent summary of the book, I will be brief in my summary but review the book more broadly.
The basis thesis of the book is simple. In judging the world around us, we use two mental systems: Fast and Slow. The Fast system (System 1) is mostly unconscious and makes snap judgments based on our past experiences and emotions. When we use this system we are as likely to be wrong as right. The Slow system (System 2) is rational, conscious and slow. They work together to provide us a view of the world around us.
So what's the problem? They are incompatible, that's what.
System 1 is fast, but easily swayed by emotions and can be as easily be wrong as be right. You buy more cans of soup when the display says "Limit 12 per customer". We are on autopilot with this system. System 1 controls an amazing array of behavior. System 2 is conscious, rational and careful but painfully slow. It's distracted and hard to engage. These two systems together provide a backdrop for our cognitive biases and achievements.
This very well written book will enlighten and entertain the reader, especially if the reader is not exposed to the full range of research relating to behavioral economics.
This book serves an antidote to Malcolm Gladwell's Blink. Although Gladwell never says that snap judgments are infallible and cannot badly mislead us, many readers got a different message. As the Royal Statistical Society's Significance magazine put it "Although Gladwell's chronicle of cognition shows how quick thinking can lead us both astray and aright, for many readers Blink has become a hymn to the hunch." While Kahneman does show how "fast thinking" can lead to sound judgments, he also notes how they can lead us astray. This point is made much more clearly and deliberately in Kahneman's book
All my admiration for the brilliance and creativity of Kahneman (and Tversky) does not mean that I accept 100% of their thesis. Consider this oft-quoted study. Linda is 31 years old, single, outspoken, and very bright. As a student, she was deeply concerned with the issues of discrimination and social justice, and she also participated in anti-nuclear demonstrations. Which is more probable? 1. Linda is a bank teller. 2. Linda is a bank teller and is active in the feminist movement. Eighty-five percent of test subjects chose the second option, that Linda was a bank teller and active in the feminist movement. Kahneman's interpretation is that this opinion is wrong because the probability of a (random) woman being a bank teller is greater that than person's being a bank teller AND a feminist. What Kahneman overlooks here is that what most people answered may not be the question that was asked. The respondents may not have been concerned with mathematical probabilities, but rather could be responding to the question in reverse: Is it more likely for a current activist to have been an activist in the past compared to others in the profession? A more formal and theoretically better argued rebuttal of some of Kahneman's hypotheses can be found in the works of Gerd Gigerenzer.
Kahneman notes that even top performers in business and sports tend to revert to the mean in the long run. As a result, he attributes success largely to luck. I'm not so convinced of this. There can be alternative explanations. People who achieve high degree of success are also exposed to a high degree of failure and the reversion to the mean may be attributable to this possible mirror effect. Spectacular success may go with spectacular failure and run-of-the-mill success may go with run-of-the-mill failure. Eventually everyone may revert the mean, but the ride can be very different. Chance may not account for that.
Another concern is that much of the work is done in artificial settings (read college students). While much of what we learnt can perhaps be extended to the real world, it is doubtful every generalization will work in practice. Some may find Kahneman's endorsement of "libertarian paternelism," not acceptable. More importantly, when applied to the real world it did not always found to work.
In spite to these comments this book is written carefully in a rather humble tone. I also appreciated Kahneman's generous and unreserved acknowledgement of Tversky's contributions and his conviction that, had he been alive, Tversky would have been the co-recipient of the Nobel Prize. My cautionary comments probably have more to do with the distortions that might arise by those who uncritically generalize the findings to contexts for which they may not applicable. As mentioned earlier, the wide misinterpretation of Gladwell's Blink comes to mind.
Nevertheless, Thinking Fast and Slow is a very valuable book by one of the most creative minds in psychology. Highly recommended. For a more complete and critical understanding, I also recommend the writings of the critics of behavioral economic models such as Gerd Gigerenzer.
PS. After I published this review, I noticed an odd coincidence between Thinking Fast and Slow and Inevitable Illusions that I mentioned in my opening paragraph. Both books have white covers, with an image of a sharpened yellow pencil with an eraser top. How odd is that?