When I first read this book, in 2011, this chapter changed my life. Or better said, I decided that this book should have to change my life. That is, unfortunately, I’m most of the time an stupid machine that jumps continuously into conclusions, but thanks to Kahneman, a few times I can stop myself in the middle of a thought and realize that “Damm you! This is the halo bias” or “Come on. How could you be so inside the confirmation bias”.
It also helped me to change habits. For example, after reading Kahneman’s observations about exams and corrections, as a teacher every time it is possible I use test exams to avoid some biases.
I’d made mandatory in every school to explain those biases and make students analyze how often those biases control their own thoughts. And here’s the main problem: it is very easy to spot those biases in other people, but so difficult to find them in our own trains of thoughts. Like Feynman said “The first principle is that you must not fool yourself, and you are the easiest person to fool”
Let me present those biases briefly:
The confirmation bias: we are cognitive machines that -by default- believe. In order to remove a belief, system 2 has to work hard. If you started thinking that the only reason of the last economic crisis was the unmitigatable greed of the evil 1%, then it is going to be very difficult for you to change views, and you’ll just interpret every further development of the crisis accordingly, paying close attention to those elements in favor of your position, and dismissing or forcing reinterpretation to those that go against it.
The halo bias. If a person, a theory or a concept is first presented with a few characteristics that are positive, then we’ll consider that other different characteristics of that person or theory have to be also positive, even if we don’t have any good reason to think so. We saw an stunning example of that when after winning the elections, Barack Obama was awarded the Nobel Prize.
The What You See is All There is bias. When facing a decision, we just pay attention to whatever is salient at the moment, and we are not able to look for other evidence that might present the problem in a different light. You consider a food that is “90% fat free” as a saludable choice, almost no fat! But then, if you could look if from another point of view, you’d realize that it has a good deal of fat: 10%
One of the corollaries of Gödel’s theorem is that if a logical system can prove of itself that it is complete, then it is inconsistent for sure. In a similar way, if a person reads this chapter and thinks that it has nothing to do with him or her, then it really has to do a lot to do with that person.