book cover
“The experiencing self does not have a voice. The remembering self is sometimes wrong, but it is the one that keeps score and governs what we learn from experience, and it is the one that makes decisions.”

Thinking Fast and Slow Book Review

Thinking, Fast and Slow, Daniel Kahneman, 2011 


The author is a Nobel Prize winner who asks us to consider how our mind habitually contradicts itself, shows prejudice, distorts data and misleads. None of which is good news!

Daniel Kahneman wants to offer a model of how our thinking works. He claims that people use two cognitive systems. He calls them System One and System Two. One is fast, the other slow. System One works easily and automatically and without too much thought; it makes quick judgments based on familiar patterns. System Two takes more effort; it requires intense focus and operates methodically.

Err that’s it, except…

So What? 

The two Systems interact. Most everyday decisions do not require too much deliberate thought. We distort the likelihood of future events and realign our memories. Our mind would appear to prefer simple stories and simple explanations. The source of many of the biases that infect our thinking. System One leads us to an intuitive conclusion based on a “heuristic” — an easy but imperfect way of answering hard questions — and then System Two lazily endorses this heuristic answer without bothering to scrutinize whether it is logical.

In short, we don’t think or act rationally.

Now What?

The book is long, quirky and full of surprises. For example, Kahneman explains how judges think they make considered decisions about parole based strictly on the facts of the case. It turns out that factors such as whether they have had lunch and their blood-sugar levels influence the leniency of their decisions.

Kahneman offers so many examples to illustrate his claim that we don’t know why we do something or what shapes our everyday behaviours.

  • Heuristics – procedures to help find answers to difficult questions and why we are susceptible to unconscious bias. For example
    • Anchoring – we habitually make associations and tie new information about a topic to recent information. We don’t know we do it. Mentioning the number 10 and then asking how many African countries belong to the United Nations will produce lower estimates than if you mentioned 65 and asked the same question.
    • Availability – is ‘the ease with which instances come to mind.’ If you have personal and recent experience of, let’s say, a judicial error, your faith in the justice system will be less secure than if you had read of exactly the same events in the newspaper. 
  • Overconfidence
    • Understanding – we build the best possible explanatory story from the available information.  When telling stories about events we are involved in, we tend to be overly optimistic and overvalue our own talents relative to others. We also will give our knowledge greater weight than it deserves.
    • Experts – most of us, even the highly sceptical, are seduced by quick answers to difficult questions.
  • Choices
    • Prospects – Kahneman argues that it’s easy to confuse experience with the memory of it. It’s a compelling illusion. Choice from experience differs from choice from description. Making good choices depends on giving attention to the source of your information.
  • Two Selves 
    • The “experiencing self” is the part of you that lives your life; the “remembering self” is the part that evaluates the experiences you have. If you listened to a musical recording in its entirety but stopped just short at the end would your experience be ruined? Or would your memory of the experience be ruined. Or neither? 

As individuals we are not great at constructive criticism. We go to judgment prematurely. For Kahneman organisations are ‘factories which manufacture judgments and decisions.’ He suggests we could benefit by acquiring a richer language for understanding how our decisions are made.