The one sentence summary

The most intelligent people can still be remarkably stupid when they fall into the intelligence trap.

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  • We assume that smarter people are less prone to error, but greater education and expertise can often amplify our mistakes while rendering us blind to our biases. This is the intelligence trap.
  • The book aims to revolutionise your thinking and enable you to make wiser decisions by being aware of the many ways in which the trap works.
  • Intelligent and educated people are less likely to learn from their mistakes or take advice from others. When they do err, they build elaborate arguments to justify their reasoning, becoming more and more dogmatic in their views. They also have a bigger bias blind spot, so they are less able to recognise holes in their logic. There are three broad reasons:
  1. Lack of creative or practical intelligence for dealing with life in general.
  2. Using biased intuitive judgments to make decisions.
  3. Using their intelligence to dismiss any contradictory evidence (‘earned dogmatism’).
  • Dysrationalia is the inability to think and behave rationally despite having adequate intelligence. Arthur Conan Doyle developed the Sherlock Holmes character whilst genuinely believing in fairies.
  • Confirmation bias, or myside bias, refers to the many kinds of tactics we use to support our viewpoint and diminish alternatives.
  • In linear sequential unmasking, forensic analysts make their judgements ‘blind’, without any knowledge of previous diagnoses, thus avoiding bias.
  • The intelligence trap has 4 potential forms:
  1. We may lack the necessary tacit knowledge and counter-factual thinking that are essential for executing a plan and pre-empting consequences.
  2. We may suffer from dysrationalia, motivated reasoning and the bias blind spot – building ‘logic tight compartments’ around our beliefs.
  3. We may place too much confidence in our judgement due to earned dogmatism, fail to note our limitations and over-reach our abilities.
  4. We use our expertise to employ entrenched automatic behaviours that render us oblivious to obvious warning signs that disaster is looming.
  • Once we work out why smart people act stupidly, and what skills and qualities they are missing that explain this, we can cultivate those skills ourselves. We need to pursue actively open-minded thinking. Those who speak a different language or have lived abroad think more openly.


  • “It is not enough to possess a good mind; the most important thing is to apply it correctly.” René Descartes
  • “A great many people think they are thinking when they are merely rearranging their prejudices.” William James


  • This is quite a detailed read. There is a lot in the book, but you have to dig for it.