How Thinking, Fast and Slow by Daniel Kahneman has supported my career

Pencil on paper

Last week I attended the Public Sector Design Community Meet-up, which was hosted by us at the University of Edinburgh. Attendees were invited to share a book, podcast or talk that has influenced or supported their career.

I chose Thinking, Fast and Slow by Daniel Kahneman.

I took some notes to help me structure my thoughts, and I’ve decided I might as well turn those notes into a blog post. I originally meant to write about this book shortly after I read it, but I didn’t have the time. So this is a good opportunity for me to at last rave about this book.

I work in user experience, a field I came into via web design.

My degree was in social sciences — economics and politics. For a long time I didn’t see the connection between that and my work. Over time, as I took more of an interest in user experience, I began to understand the connections between my degree and my work as a designer.

So I have chosen a book by a Nobel economics prize winner, Daniel Kahneman — Thinking, Fast and Slow.

It’s not directly about user experience or design. But I have chosen it as it brought things full circle for me. Because here I was reading an economics book and thinking about how applicable it was to my work.

User experience is a social science — it’s a study of people. Daniel Kahneman, along with his long-time colleague Amos Tversky, has done a great deal to advance our understanding of people.

Thinking, Fast and Slow is essentially a summary of his life’s work. This makes it an essential read if you want to understand people better. And if you’re working in user experience or design, that should mean you.

Daniel Kahneman won the Nobel prize in economics despite not being an economist, and not even having taken an economics course.

His key contribution was to turn economists’ understanding of human behaviour on its head. Economists had clasically believed in homo economicus, or economic man. This is a person who makes decisions on a rational basis, using a set of rules defined by rational choice theory.

Daniel Kahneman knew differently. In coming into contact with economists, he saw the need to correct their assumptions. In doing so, he popularised the field of behavioural economics, and completely transformed the way economists think about people.

Daniel Kahneman’s insights

Here are just a handful of his interesting findings, described in the book.

Different modes of thinking

This is the fast and slow described in the title. ‘Fast’ thinking is known as system 1; ‘slow’ is system 2. These two systems are completely different ways of thinking when we are carrying out tasks.

Interestingly, complex thoughts can be done in system 1 — such as making a good chess move, if you’re good at chess.

Similarly, some easy tasks are system 2 tasks — like counting the number of As in a text.

What you see is all there is

This phrase comes up a lot in the book. It describes how our thinking is dominated by information that is immediately available to us. Reading the book, I began to think of it as a more formal version of Don’t Make Me Think, the name of Steve Krug’s highly influential usability book.


Daniel Kahneman and Amos Tversky did a lot of work around understanding various biases.

The framing effect is particularly useful for those of us who conduct user research. It shows just how much the framing of a question can skew what a participant will say to you.

  • Would you go for surgery if the survival rate is 90%?
  • Would you go for surgery if the mortality rate is 10%?

The facts in these two questions are the same. They are just worded differently. But they yield very different responses from people.

This shows us how easy it is to lead people with a carelessly-framed question in an interview or survey.


The section on overconfidence demonstrates how people overestimate how much they know about the world. I think many people could do with reminding of this. And it’s a reminder of why we should do research before charging ahead.

The distinction between the experiencing self and the remembering self

What we remember does not necessarily align with what we actually experienced. Of particular interest is the peak–end rule.

Take this example of two patients experiencing a painful colonoscopy. Patient A experiences a great deal of pain for less than 10 minutes, ending on a particularly painful note. Patient B has a similar experience for 15 minutes, and then 10 minutes of milder pain.

Patient B rates their procedure as less painful than Patient A — even though they experienced more pain over a longer period of time. This is because how we remember an experience is heavily influenced by how it ended.

Daniel Kahneman said, “I am my remembering self. The experiencing self, who does my living, is like a stranger to me.”


In summary, people are interesting! And far more complicated than you think. So we should go out and find out more about them.


4 responses to “How Thinking, Fast and Slow by Daniel Kahneman has supported my career”

  1. […] Read Duncan’s blog post on Thinking, fast and slow […]

  2. […] fashionable to dismiss rational choice theory out of hand. I’m a big fan of Daniel Kahneman, whose work has done so much to detail its limitations. But contrary to what you may have been […]

  3. […] Book review of Thinking, Fast and Slow from my own blog […]

  4. […] you’ve read the book Nudge — or perhaps Thinking, Fast and Slow — you’ll have come across the idea before. The nudge intern is going to help us apply […]

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