Thinking, Fast and Slow. Daniel Kahneman (2011)

What it argues

That human judgement runs on systematic shortcuts, and that the errors those shortcuts produce are predictable rather than random.

For marketing the consequences are direct. Most purchasing runs on the fast system. People do not weigh attributes, they retrieve a feeling and then construct a reason. Which means the job is usually not to win an argument but to be easy to retrieve and comfortable to choose.

The specific mechanisms matter more than the framework. Anchoring, availability, loss aversion and framing are each testable and each show up in pricing, packaging and copy.

What it gets right

Loss aversion and anchoring have held up well and are among the better evidenced findings in the social sciences. The general point that stated preference is a poor guide to behaviour is something marketing research still has not fully absorbed, forty years on.

The book is also unusually honest about uncertainty for a popular science title, and Kahneman was careful to present System 1 and System 2 as a useful fiction rather than as two places in the brain.

What is wrong with it, and this is the part that matters

Part of this book did not survive replication, and Kahneman said so himself.

The chapter on social priming, the work suggesting that subtle cues like words about ageing change subsequent behaviour, was built on studies that have largely failed to replicate. In 2017 Kahneman publicly acknowledged that he had placed too much faith in underpowered studies and that readers should not believe that chapter as written.

That is an extraordinary thing for an author to say and it is to his enormous credit. It is also routinely omitted when marketers cite the book, which is how priming claims continue to circulate in the trade years after the evidence collapsed.

So: cite loss aversion, anchoring and availability with confidence. Treat the priming material as superseded. And be suspicious of anybody who cites this book without knowing the difference.

Who should read it, and who should not

Read it if you set prices or write offers. The chapters on anchoring, framing and loss aversion will pay for themselves.

Read it critically. This is the book in the trade most often quoted by people who have not read it.

Do not use it to justify manipulation dressed as insight. The mechanisms work regardless of whether what you are selling is good, which is an argument for care rather than for enthusiasm.

The soundbite

The fast mind decides and the slow mind writes the justification, which is why asking people why they bought is close to useless.

If you run the company rather than the marketing

Two things from this book are worth your attention and the rest is interesting rather than actionable.

Stated preference is a poor guide to behaviour. If a decision in your company rests on what customers said in a survey or a focus group, it rests on something weaker than it appears. What people do and what they report doing diverge systematically, not randomly. Prefer observed behaviour wherever you can get it.

Framing changes the answer. The same offer presented as a gain and as an avoided loss produces different responses. That applies to your pricing, your renewal conversations and your proposals, and it is nearly free to test.

The warning I would attach is about how this book gets used internally. It has become the standard citation for any claim that buyers are irrational, usually to justify a decision somebody wanted to make anyway. Kahneman himself retracted confidence in one of its chapters. Anyone quoting it as settled science on every point has not read it closely.