The Knowledge Illusion Book Summary - The Knowledge Illusion Book explained in key points
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The Knowledge Illusion summary

Steven Sloman & Philip Fernbach

Why We Never Think Alone

4.6 (93 ratings)
31 mins

Brief summary

"The Knowledge Illusion" by Steven Sloman and Philip Fernbach explores how we think and what we know, arguing that we rely heavily on other people and the internet to fill gaps in our understanding. This enlightening book shows that our individual knowledge is actually a collective illusion.

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    The Knowledge Illusion
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    The illusion of explanatory depth causes us to think we know more than we actually do.

    You can probably ride a bicycle. Most people can – after all, it’s a pretty straightforward activity. Once you master the balance part, simply hop on, push the pedals and off you go. So it stands to reason that you could explain how a bicycle works, right?

    Well, you might be surprised. Here’s the thing: people have a habit of overestimating how much they know about how things work, even when they don’t know much at all. This gap between assumed understanding and actual knowledge is called the illusion of explanatory depth, or IoED, for short.

    To get an idea of how the IoED works, let’s return to the matter of bikes.

    At the University of Liverpool, a psychology professor named Rebecca Lawson put her students’ knowledge to the test by handing out copies of a drawing. It depicted an incomplete bicycle, which lacked, among other parts, a chain, pedals and sections of the frame. She then asked her students to complete the drawing.

    The resulting drawings varied in accuracy. One had two sets of pedals; another lacked crucial parts of the frame. Few would have fared well on the open road.

    This led the students to an uncomfortable realization: they were unable to articulate knowledge that they’d been sure they possessed, and their understanding was in fact quite shallow. That’s the IoED in a nutshell.

    How a bicycle works is just one of many things that people, when put to the test, have difficulty explaining. Other tests have revealed that people overestimate their knowledge of all sorts of everyday objects, from zippers to toilets to wristwatches. Indeed, people tend to overestimate their knowledge of everything.

    The inevitable conclusion to be drawn from this fact? People don’t know as much as they think they do.

    This leads us to a question that bedeviled early cognitive scientists: how much do we know?

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    What is The Knowledge Illusion about?

    The Knowledge Illusion (2017) is an in-depth exploration of the human mind. It argues against the view that intelligence is solely an individual attribute, offering compelling arguments for how our success as a species would have been impossible without a community of knowledge.

    The Knowledge Illusion Review

    The Knowledge Illusion (2017) explores the surprising truth about what we actually know and how we think. Here's why this book is worth reading:

    • By revealing our collective ignorance, it challenges our assumptions and forces us to question our own knowledge.
    • With its insightful analysis of how the mind works, it provides a fresh perspective on decision-making, problem-solving, and understanding the world.
    • Through its examination of group intelligence and the power of collaboration, it offers valuable insights into how we can tap into collective knowledge for better outcomes.

    Best quote from The Knowledge Illusion

    A good story has a moral that applies not just to this world but also to other worlds that we might find ourselves in.

    —Steven Sloman & Philip Fernbach
    example alt text

    Who should read The Knowledge Illusion?

    • Students of cognitive science
    • Know-it-alls
    • Aspiring intellectuals worried that they know too little

    About the Author

    Steven Sloman, a professor of cognitive linguistics, teaches at Brown University. He is also the editor of Cognition, a scientific journal dedicated to the study of cognitive science.

    Philip Fernbach is an assistant professor at the University of Colorado, where he teaches marketing.

    Their collaborative work has been featured in the New York Times, the Atlantic and Slate, among other publications.

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    The Knowledge Illusion FAQs 

    What is the main message of The Knowledge Illusion?

    The main message of The Knowledge Illusion is that we often overestimate our own knowledge and underestimate the role of collective intelligence.

    How long does it take to read The Knowledge Illusion?

    The reading time for The Knowledge Illusion varies, but it typically takes several hours. However, the Blinkist summary can be read in just 15 minutes.

    Is The Knowledge Illusion a good book? Is it worth reading?

    The Knowledge Illusion is a thought-provoking read that challenges our understanding of knowledge. It offers valuable insights into how our minds work and the importance of collaboration.

    Who is the author of The Knowledge Illusion?

    The authors of The Knowledge Illusion are Steven Sloman and Philip Fernbach.

    What to read after The Knowledge Illusion?

    If you're wondering what to read next after The Knowledge Illusion, here are some recommendations we suggest:
    • The Social Animal by David Brooks
    • The Upside of Irrationality by Dan Ariely
    • Irrationality by Stuart Sutherland
    • The Invisible Gorilla by Christopher Chabris and Daniel Simons
    • The Intelligence Trap by David Robson
    • The Psychology of Money by Morgan Housel
    • You Are Not So Smart by David McRaney
    • The 5 AM Club by Robin Sharma
    • If You’re So Smart, Why Aren’t you Happy? by Raj Raghunathan
    • How Highly Effective People Speak by Peter Andrei