This book gives a really good framework to understand the way the human mind works. It starts with the story of two psychologists who questioned the conventional wisdom at the time: primarily the belief that professionals with a lot of experience are infallible and can completely be trusted. Amos Tversky and Daniel Kahneman developed many experiments that shed light on the various biases that the human mind is susceptible to (even in people with thousands of hours of experience in a certain field).

By describing the human mind’s behavior, and going through various experiments these psychologists subjected their grad students to, they provide a really good framework for understanding how our mind works. However, it is always a lot easier to see these biases in others.

Furthermore, by providing terms such as the “recency effect”, “framing bias”, “availability bias” (and many, many more), they allow us to grasp these behaviors through language by labeling them and being able to better spot them.

Here are some of my notes from this book.

A Tale of Two Systems

Most importantly, the book starts by describing the mind as two systems, system 1 and system 2. This can be vaguely similar to the conscious and the unconscious. System 2 is the active conscious mind: this contains our daily sensations, thoughts, and feelings that we are completely aware of. When we are actively involved in our experience and aware of being aware. System 2, is correlated with a dilation in the pupils. It is an energy expensive system to the brain, that many of us don’t use all the time (due to its energy cost), we only use system 2 when we are actively concentrating.

The rest of the time, we are engaged in system 1, aka auto-pilot behavior, we are not 100% conscious of what’s happening, just vaguely enough to proceed with the correct actions. System 1 has evolved in humans to be accurate a lot of the time, and it helps us deal with daily life without using much energy. However, system 1 is susceptible to many biases, even among experienced professionals (doctors, economists, and many other experts who these two psychologists showed to be susceptible).

Math problems and difficult decisions engage system 2, the rest of the time, about 80% or so, we are in system 1. System 1 works by approximations and by looking at the past to predict the future.

What You See Is All There Is

System 1 is a story-teller, it functions by creating a narrative even when the information is unreliable. The narrative is always compelling regardless of the evidence’s value. We usually measure the reliability of the evidence based on the narrative constructed rather than the evidence it was constructed on. “What you see is all there is” describes this phenomenon: we usually believe the story as all there is when reality can be much more complex. For example, we form an impression of a person within the very first few seconds of meeting them. We clearly form these impressions with inadequate information, based on facial expressions and feelings. We evolved these impressions as they can be very useful, but still inaccurate at times.

Thinking slowly, in organizations

The author gives some good examples of “thinking slowly”, he describes that organizations must develop processes to improve decision making and try to overcome groupthink. Many of these ideas are describes by Daniel Kahneman in this article in the Harvard Business Review