Thinking, Fast and Slow Summary

Daniel Kahneman

Thinking, Fast and Slow

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Thinking, Fast and Slow Summary

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In Thinking, Fast and Slow, psychologist Daniel Kahneman explains how two systems of human mind constantly fight each other. The fighting negatively affects the clarity of our thinking. He reveals how this knowledge of how our brain functions can affect choices we make in both our personal lives and in business. The book, by a Nobel Prize winner in economics, was selected by the New York Times as one of the top ten books of 2011 and won the National Academy of Sciences Best Book Award.

The central thesis of the book is humans have two opposing modes or systems of thought: fast thinking and slow thinking—thus, the title of the book. Every behavior and action we take is controlled by two different systems in our brain, which rather than working together, constantly fight each other. The fighting causes us to make mistakes and poor decisions. These two systems influence all our decisions and our ability to make judgments.

“System 1” is fast, intuitive and controlled by our emotions. This first system is automatic and subconscious. It is what helped us survive in our past. System 1 skills are often primitive and include judging the distance of objects, detecting danger, or finding the source of a sudden sound. System 1 thinking was a form of survival. Other fast thinking skills we gain through practice and experience, for example, solving simple arithmetic problems, understanding simple sentences, or driving a car on an empty road. Expertise can also enable a person to make quick and complex decisions. The perfect example is a chess master who knows the next move to make in a game.

“System 2” is slow, deliberate, and controlled by logic. As a much more recent addition to our brain, it is much less primitive than System 1. It is conscious and takes effort. It is the complex mathematical calculation versus simple arithmetic. It is driving on an unfamiliar road in the midst of a snowstorm. It is understanding a complex and logical argument.

The majority of the book focuses on how System 1 and System 2 interact with each other. When we are awake, both systems are on. System 1 is running at all times automatically and effortlessly in the background. System 2, which uses more energy, is on standby waiting to be needed. When System 1 encounters something surprising, System 2 stops idling and takes charge. System 2 always gets the final say once it is put to use. These two systems evolved over hundreds of years of human evolution. They work extremely well in minimizing effort and maximizing our performance. They work like a well-designed system—most of the time.

The problem with the two systems is that System 1 has a tendency to keep control when it should allow System 2 to take over. In other words, our intuition cannot always be trusted. It can sometimes lead us to make the wrong conclusion or come up with the wrong answer.

In familiar environments or situations, System 1 is very good at making predictions or giving us an accurate assessment. But, and this is a big but, we cannot turn System 1 off. To make an informed decision, there are times when we need to also use slow thinking fueled by logic. System 2 is able to override the biases of System 1. But it is too exhausting to use System 2 all the time. Our brains get lazy. This laziness causes us to make errors in judgment. Kahneman wants us to realize that we are often less rational than we think.

Errors in our thinking can affect all areas of our lives. Kahneman points out that we have cognitive biases, systematic errors in our thinking. These biases can negatively influence our thinking and decision-making in all areas of work and our personal lives. One of our important cognitive biases is that we have a pervasive optimistic bias, which causes us to be unrealistically optimistic. We believe we are less likely to experience a negative event than others. It gives us a false illusion of control over our lives. An example of this is the planning fallacy, where we underestimate the amount of time (or money) needed to complete a future task.

We also have “heuristics,” or rules of thumb, which can cause us to jump to conclusions. Sometimes these conclusions are right and other times they are wrong. Fast thinking is often necessary, and it not always wrong. Kahneman shares that recent discoveries in both cognitive and social psychology show the marvels of intuitive thinking.

Thinking, Fast and Slow does not only point out the problems in our thinking. Kahneman also offers different techniques to prevent us from letting our thinking get us into trouble.

In 2002, Daniel Kahneman won the Nobel Prize in Economic Sciences for his pioneering research combining economics and psychology. In particular, Kahneman focused on how we make judgments and decisions under uncertainty. Currently, he is a senior scholar at the Woodrow Wilson School of Public and International Affairs.