The Extended Mind: The Power of Thinking Outside the Brain

by Annie Murphy Paul

I entered into one such intimate exchange when I read, with a jolt of recognition, a passage written more than 130 years ago; it was as if the author were reaching through the pages that lay open on my desk. Making the meeting more intense, the writer in question was a distinctly intimidating character: the German philosopher Friedrich Nietzsche, he of the severe gaze and vaguely sinister mustache.

I encountered his words as I was working on a chapter about how bodily movement affects the way we think. The quote from Nietzsche appears in a book titled A Philosophy of Walking, by the contemporary French philosopher Frédéric Gros; Gros has his own thoughts to add. Don’t think of a book as issuing only from an author’s head, he advises. “Think of the scribe’s body: his hands, his feet, his shoulders and legs. Think of the book as an expression of physiology. In all too many books the reader can sense the seated body, doubled up, stooped, shriveled in on itself.”

Nietzsche, he reminds us, wrote that we should “sit as little as possible; do not believe any idea that was not born in the open air and of free movement.”

This book argues otherwise: it holds that the mind is something more like the nest-building bird I spotted on my walk, plucking a bit of string here, a twig there, constructing a whole out of available parts. For humans these parts include, most notably, the feelings and movements of our bodies; the physical spaces in which we learn and work; and the other minds with which we interact—our

social critic Susie Orbach senses what her patients are feeling by tuning in to the internal sensations of her own body (a capacity known as interoception).

Robert Caro plots the lives of his biographical subjects on an intricately detailed wall-sized map.

First, there is the study of embodied cognition, which explores the role of the body in our thinking: for example, how making hand gestures increases the fluency of our speech and deepens our understanding of abstract concepts.

distributed cognition, which probes the effects of thinking with others—such as how people working in groups can coordinate their individual areas of expertise (a process called “transactive memory”),

As a journalist who has covered research in psychology and cognitive science for more than twenty years, I read the findings generated by these fields with growing excitement. Together they seemed to indicate that it’s the stuff outside our heads that makes us smart—a

“there is nothing sacred about skull and skin.” Elements of the world outside may effectively act as mental “extensions,” allowing us to think in ways our brains could not manage on their own.

During my many years of reporting, I had never before encountered an idea that changed so much about how I think, how I work, how I parent, how I navigate everyday life. It became apparent to me that Andy Clark’s bold proposal was not (or not only!) the esoteric thought experiment of an ivory tower philosopher; it was a plainly practical invitation to think differently and better.

In time I came to recognize that I was acquiring a second education—one that is increasingly essential but almost always overlooked in our focus on educating the brain.

Frédéric Gros, the French philosopher who brought Nietzsche’s words to my attention, maintains that thinkers ought to get moving in a “quest for a different light.”

As long as we settle for thinking inside the brain, we’ll remain bound by the limits of that organ. But when we reach outside it with intention and skill, our thinking can be transformed. It can become as dynamic as our bodies, as airy as our spaces, as rich as our relationships—as capacious as the whole wide world.

Thinking outside the brain means skillfully engaging entities external to our heads—the feelings and movements of our bodies, the physical spaces in which we learn and work, and the minds of the other people around us—drawing them into our own mental processes. By reaching beyond the brain to recruit these “extra-neural” resources, we are able to focus more intently, comprehend more deeply, and create more imaginatively—to entertain ideas that would be literally unthinkable by the brain alone.

The human brain is limited in its ability to pay attention, limited in its capacity to remember, limited in its facility with abstract concepts, and limited in its power to persist at a challenging task.

We urge ourselves and others to grit it out, bear down, “just do it”—to think harder. But, as we often find to our frustration, the brain is made of stubborn and unyielding stuff, its vaunted plasticity notwithstanding. Confronted by its limits, we may conclude that we ourselves (or our children or our students or our employees) are simply not smart enough, or not “gritty” enough. In fact, it’s the way we handle our mental shortcomings—which are, remember, endemic to our species—that is the problem. Our approach constitutes an instance of (as the poet William Butler Yeats put it in another context) “the will trying to do the work of the imagination.” The smart move is not to lean ever harder on the brain but to learn to reach beyond it.

Schools don’t teach students how to restore their depleted attention with exposure to nature and the outdoors, or how to arrange their study spaces so that they extend intelligent thought.

Dweck’s idea, which she initially called “the incremental theory of intelligence,” would eventually become known to the world as the “growth mindset”: the belief that concerted mental effort could make people smarter, just as vigorous physical effort could make people stronger.

“The key message was that learning changes the brain by forming new connections, and that students are in charge of this process.”

For one thing: thought happens not only inside the skull but out in the world, too; it’s an act of continuous assembly and reassembly that draws on resources external to the brain. For another: the kinds of materials available to “think with” affect the nature and quality of the thought that can be produced. And last: the capacity to think well—that is, to be intelligent—is not a fixed property of the individual but rather a shifting state that is dependent on access to extra-neural resources and the knowledge of how to use them.

Engaging in brain training does improve users’ performance—but only on exercises highly similar to the ones they’ve been practicing. The effect does not seem to transfer to real-life activities involving attention and memory. A 2019 study of Cogmed concluded that such transfer “is rare, or possibly inexistent.”

We extend beyond our limits, not by revving our brains like a machine or bulking them up like a muscle—but by strewing our world with rich materials, and by weaving them into our thoughts.