Book Review: “Thinking, Fast and Slow” by Daniel Kahneman

As with all of my Book Reviews, this blog post is not really a review, it is a summary of the book, briefly explaining each chapter.

The reasons for me writing this post are rather selfish:

  • To help me get more from the book by forcing me to STUDY it, not just READ it
  • To have a place that I can refer to in the future if I want to remind myself about it.
  • To summarise any findings that I believe will help in my Kleeneze business.

So I am pleased if you find it helpful, but I’m afraid I make no apology if you don’t.

thinking fast and slow





1. The characters of the story

Your mind has two different ways of judging, choosing, and thinking about things.

  1. The first, which is your initial reaction to an event, your immediate response, your intuition. In the book this is called “System 1
  2. The second, which is logical, thoughtful, and reasoning. This is referred to as “System 2

2. Attention and effort

System 1” is easy, and takes little effort. “System 2” takes significant mental effort.

As a result, we often make decisions based on our intuition, or gut feeling, rather than spending time engaging our logical mind and going through the pros and cons, as that seems too much like hard work.

3. The lazy controller

When we are tired, towards the end of a day perhaps, we are even more likely to revert to intuition and gut feeling, as we are too tired to engage System 2.

4. The associative machine

You can be primed to think about something in a certain way. Putting a smile on your face, will then cause you to enjoy an experience more than if you force a frown on your face before the experience.

5. Cognitive ease

If you find it easy to think about something – for example…

  • if it is an idea you have come across before,
  • if you have been primed,
  • if you are in a good mood,
  • if the display is clear and easy to understand,

….then you are more likely to think it is true, it feels familar, it feels good, and it feels effortless.

So things become more believable if they are written in a clear font, and are repeated.

6. Norms, surprises and causes

It only takes one unusual occurance, for that event to seem normal the next time it happens.

7. A machine for jumping to conclusions

System 1 has a habit of jumping to conclusions, which can be corrected if you take some time to engage System 2. Often you will base a decision on limited information, because that information is all you have to go on. Rather than seek out more information, you will decide, based on the information that you have.

8. How judgements happen

The author introduces the concept of a Mental Shotgun – your System 1 will often do far more work than it needs to, to make a simple decision.

9. Answering an easier question

We are rarely stumped for an answer (or an opinion). If we are asked a question to which we do not know the answer, we will search for a simpler question to which we do know the answer, and substitute that question for the harder one. We use heuristics (our own experiences) to find a question we can answer, and then relate that to the original question.

10. The law of small numbers

The Law of small numbers tells us that we will often search for, or assume, a cause for a statistic, when in fact it is simply a statistical anomaly because of the small sample size. There is a difference between Cause, and Chance.

11. Anchors

If you are considering a question, and you are asked about a number first, that number will affect your judgement of the question. The number is called an anchor.

That is why in marketing, a product will often be shown as “previously £15, now only £9.99” The £15 makes you think you are getting a bargain so you may buy it, whereas simply seeing a price of £9.99 may not persuade you.

12. The science of availability

The ease with which examples come to mind determines how often you think certain events happen. However, that can simply be the strength of the media. You hear in the media about aeroplane accidents because they are so dramatic, so you think they happen frequently. In fact they are relatively infrequent.