The Extended Mind: The Power of Thinking Outside the Brain
By Annie Murphy Paul
Houghton Mifflin Harcourt, 2021

I grew up thinking the mind and body were separate things — that thoughts, ideas, consciousness, etc. happen exclusively in the meat computer between the ears, which commands the rest of the body. This view, which has been pervasive for a long time, posits the brain as a sort of puppeteer controlling (and receiving signals from) the body. Recent research suggests this reductionist view of the mind is wrong.

In a 1998 paper titled The Extended Mind, Andy Clark and David Chalmers proposed an alternative philosophy of mind. Their extended mind thesis (EMT) posits that the body and the physical world also play an essential role in cognition. It’s an important theory that has many practical implications.

Annie Murphy Paul’s book, which is also titled The Extended Mind, clearly explains the research and draws out those implications. The book aims “to operationalize the extended mind, to turn this philosophical sally into something practically useful.” It succeeds in this goal. In the process, it explores the nature of technology and expertise, and the inequalities inherent in how we extend our minds.

The book starts with an examination of the metaphors we use when talking about the brain. (Metaphors reveal — and constrain — our thinking about subjects.) We mostly use two metaphors when talking about the brain:

  • The brain as a computer, which has “software,” “hardware,” etc.
  • The brain as a muscle, which we can develop through exercise

Paul suggests a potentially more useful metaphor: the brain as magpie, a bird that builds nests by “fashioning their finished products from the materials around them, weaving the bits and pieces they find into their trains of thought.” So, too, our minds fashion thoughts by interacting with our environments.

Eurasian Magpies near their nest, in the municipal park of Mouscron, Belgium. Photo by [Jamain]( via [Wikimedia]( ([CC BY-SA 3.0](

Eurasian Magpies near their nest, in the municipal park of Mouscron, Belgium. Photo by Jamain via Wikimedia. (CC BY-SA 3.0).

The book is divided into three parts, each containing three chapters. Each part focuses on different aspects of how we think beyond the brain.

Part one deals with thinking with the body. The focus is on gut feelings, which scientists call interoception. The body knows what’s going on — even if we don’t consciously understand why. We can develop the ability to tune into what our body is telling us, and doings so can make us more resilient.

How we move our bodies also affects how we think. As Paul puts it, “thinking while moving brings the full range of our faculties into play.” Alas, much of our built world assumes we think best when we’re sitting still. We sit to work, to learn, to eat, etc. We’d think better in environments that engage more of the body, and by taking active breaks (e.g., going for a walk) during the workday. (One of the few silver linings of the pandemic for me has been the ability to institute a constitutional as part of my daily routine.)

Bodily gestures (e.g., with our hands) are also an important part of our thinking. Gestures “don’t merely echo or amplify spoken language; they carry out cognitive and communicative functions that language can’t touch.” We gesture spontaneously since we’re young, but we can also be intentional in our gesturing, which can reinforce cognitive tasks such as memorization.

Part two of the book deals with thinking with environments. As Paul puts it,

all of us think differently depending on where we are… while a laptop works the same way whether it’s being used at the office or while we’re sitting at a park, the brain is deeply affected by the setting in which it operates.

Natural environments replenish our cognitive capacities. Even though humans evolved in nature, today we only spend around 7% of our time in natural environments. For a long time, we’ve designed environments that evoke or mimic nature. We ought to visit natural environments more often, but must do so while leaving our devices behind to be truly engaged.

But we can also configure built environments to support better thinking. Paul offers examples, including the Salk Institute for Biological Studies, which Louis Kahn designed to evoke a medieval monastery, and cites the emergent field of neuroarchitecture, which examines how the brain responds to built environments and how evolution may have shaped those responses.

The Salk Institute in La Jolla, California, which I visited in while participating in the 2014 Information Architecture Summit.

The Salk Institute in La Jolla, California, which I visited in while participating in the 2014 Information Architecture Summit.

This work has obvious implications for our lives. For example, open-plan offices aren’t conducive to good thinking, since we’re more likely to be distracted in environments where we lack privacy and quiet. The ideal environment for thinking is one where we can have a place to call our own — “the home advantage” — where we can focus.

Another way in which physical environments affect our thinking is by explicitly using them as a cognitive extension. This includes the method of loci (or memory palace) for memorization, or using a whiteboard or wall to externalize our ideas onto physical space. As Stanford University psychology professor Barbara Tversky put it, “When thought overwhelms the mind, the mind uses the world.”

Such techniques work because they activate parts of our brains that deal with spatial memory and navigation. Again, Tversky:

We are far better and more experienced at spatial thinking than at abstract thinking. Abstract thought can be difficult in and of itself, but fortunately it can often be mapped onto spatial thought in one way or another. That way, spatial thinking can substitute for and scaffold abstract thought.

Part three deals with thinking with other people. This includes experts (i.e., people who know more than we do about the task at hand), our peers (e.g., fellow students), and groups (“socially distributed cognition” — i.e., “the way people think with the minds of others.”) As Paul puts it,

Our brains evolved to think with people: to teach them, to argue with them, to exchange stories with them. Human thought is exquisitely sensitive to context, and one of the most powerful contexts of all is the presence of other people. As a consequence, when we think socially, we think differently — and often better — than when we think non-socially.

While understanding this benefits everyone, it’s especially important for people like me who teach others. Chapters 7-9 offer concrete practices I’ll apply in my systems course and workshops. For example, I plan to create opportunities for students to teach each other (as opposed to having me lecture while they listen passively.) There are also obvious implications of this work for all sorts designers, including architects, interior designers, interaction designers, and… well, really anyone who designs anything meant to be used by people.

And that’s one of the aspects of The Extended Mind I loved: Paul makes explicit the implications and practical uses of EMT research. And they’re not just applicable to individual development; they also have social implications. If we know that the external world plays an important role in our thinking, we should strive to make environments for good thinking more widespread.

A quote in the book from Bruno Bocanegra, professor of psychology at Erasmus University, nicely captures its core argument:

Much more than we usually recognize, humans use their environment to solve problems — an environment that is both material and social. When you see things that way, it starts to seem very silly to think that we can measure intelligence as some internal, intrinsic, individual quality.

We could do a lot more to improve society by improving the environments in which people act. This includes us, of course. Changing where we think — and how our bodies inhabit those spaces — changes how we think. Becoming more aware of how our minds work in the world can help us craft a world that is more conducive to better thinking. A virtuous cycle ensues.

These are important ideas, and The Extended Mind is the clearest and most engaging introduction I’ve read to this area of scientific research. Highly recommended.

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