What’s Reality? Make Your Best Guess
How the Brain Really Works. Reviewing ‘The Experience Machine’ by Andy Clark
If you’ve ever caught a baseball, you know how fast the brain performs amazing, advanced, mathematical calculations. Imagine you’re playing shortstop. As the batter swings, your brain notes the angle of the bat and, using various fixed points in view, the velocity of the ball after it’s hit; taking the angle and speed into account, it then plots a trajectory with basic trigonometric and geometric computations, giving you the precise location you’ll need to reach the ball. All that in a blink!
Just kidding.
Your brain doesn’t do jack with math when you’re catching a baseball. You just take your best guess about where the ball is headed and get into position. Sounds simple, maybe even unimpressive, but as philosopher Andy Clark argues in The Experience Machine: How Our Minds Predict and Shape Reality there’s something astonishing about that guess.
What your brain actually does when a batter sends a ball somewhere over centerfield is make a series of guesses—predictions—as fast as your neurons can fire about the position and speed of the ball, revising the predictions as you race toward it and generate more data from your eyes and moving body. If your guesswork and the ball converge, you’ll feel a satisfying thump in your mitt. There’s no math, just checking your relative position against where you expect to see the ball.
That’s pretty much how the brain does everything, according to the emerging consensus from neuroscience. Through academic books, papers, and lectures, Andy Clark has long helped shape that consensus and now offers a popular account of the brain’s predictive process.
Old Model, New Model
What of the prior consensus? “For much of human history, scientists and philosophers saw perception as a process that worked mostly ‘from the outside in,’ as light, sound, touch, and chemical odors activate receptors in eyes, ears, nose, and skin, progressively being refined into a richer picture of the wider world,” explains Clark. According to this view, our senses act like windows that let in an image of the world recognizable by our brain.
The new view sees the brain playing a more active role in perception—proactive, in fact. Instead of simply receiving and processing sensory data, the brain anticipates the world it experiences. It works from inside out. We’re in a constant state of predicting what’s next. “Whereas sensory information was often considered to be the starting point of experience,” says Clark,
the emerging science of the predictive brain suggests a rather different role. Now, the current sensory signal is used to refine and correct the process of informed guessing (the attempts at prediction) already taking place. It is now the predictions that do much of the heavy lifting. According to this new picture, experience—of the world, ourselves, and even our own bodies—is never a simple reflection of external or internal facts. Instead, all human experience arises at the meeting point of informed predictions and sensory stimulations.
Clark begins by offering several exercises that demonstrate this predictive function of the brain, along with how and why it works. To state it simply, there’s way too much world out there for our brains to process. So they don’t. Instead, they keep sketches of what to expect based on accumulated experience—such as, say, fielding baseballs, driving the car, walking up stairs, running down streets, watching birds soar overhead, or reading your spouse’s facial expressions.
Prediction allows the brain to take in less information. Instead of trying to process all incoming data, it only looks for variances from its predictions. Those variances, called prediction errors, provide feedback necessary to refine the model. “The brain is constantly painting a picture,” says Clark, “and the role of the sensory information is mostly to nudge the brushstrokes when they fail to match up with the incoming evidence.”
Clark then looks at how this understanding of the brain helps explain otherwise puzzling aspects of human experience, including chronic pain, the placebo effect, post-traumatic stress syndrome, autism, even schizophrenia—most of which represent miscalibrations in the predictive process.
When the predictive process is working correctly, however, it helps us set goals and act in the world, conceiving of actions and bringing them to completion. It enables our emotional responses, helping us create feelings and shape the meaning of events and occurrences. It even helps explain consciousness, which may primarily involve our brain’s turning its predictive powers onto itself. Could self-awareness simply be our brain’s best in-the-moment guess about what we think, feel, and imagine?
Shaping Daily Experience
One valuable realization trailing this understanding is the agency it lends us all in shaping our experience. If our experience is affected by our expectations, we can improve it by changing our expectations. More than an opportunity, this is something of an obligation. We’re not starting at zero. The same predictive process that allow us to construct our picture of the world also subjects us to a whole host of cognitive biases, some of which can cause us problems.
It also helps us realize that our conception of the world is not exclusively or exhaustively correct. As the product of our unique assumptions and prior personal experiences, how could it be? “That does not mean we can never get things wrong,” says Clark, as if we’re living in a world of complete subjectivity. “But it does mean that there is no single way of getting things right.”
All our perceptions are provisional and perspective-dependent. Clark includes a line from The Magician’s Nephew as an epigraph to make the point. “What you see and what you hear depends a great deal on where you are standing,” says C. S. Lewis. “It also depends on what sort of person you are.”
Clark offers several examples of how we can “hack” the predictive process to create better outcomes for ourselves, including the placebo effect, meditation, reframing exercises, even psychedelics. By far, however, for me the most exciting insights relate to what Clark terms “the extended mind,” the idea that the tools we employ on a regular basis become part of our prediction machinery and amplify our brain’s capabilities.
“We all rely, to greater or lesser degrees, upon a wide array of apps, tools, and other ‘beyond the brain’ resources to carry out our daily projects, to organize our lives, and to remember to do things that we’d otherwise forget,” says Clark, adding:
Some of these aids function in ways that seek to replicate or bolster skills and abilities already possessed by our biological brains. Others play even more intriguing roles—not simply replicating native biological capabilities but enhancing and transforming them.
When the coupling with key tools and technologies is robust and reliable, so that the brain learns to simply expect the presence of those resources, factoring their effects into all our planning and actions, we become . . . extended minds—cyborg or hybrid minds created without the need for invasive implants.
As examples, Clark mentions a dyslexic tech entrepreneur who depends upon Grammarly and SwiftKey to help her navigate the world of words and Alzheimer’s patients who counter their dementia with supportive aids such as notes and photos which compensate for their failing memories.
We learn a lot about the way our brains work by studying cases of breakdown or malfunction. The extended mind is no different. But it’s not just people struggling with dyslexia and dementia who rely on tools to extend their brain’s predictive powers; we all do.
Our brain’s ability to predict future states and imagine counterfactuals allows us to pursue goals. Any tool we use to expand that capability becomes part of our cognitive machinery, especially if we use it enough to naturally presuppose the extended capabilities when we sit down to work. Smartphones provide a preeminent example, but so do our books, notebooks, and other tools.
“Predictive brains repeatedly spin extended problem-solving webs that combine practical and epistemic actions,” says Clark, “pulling in key resources such as pencil, paper, apps, smartphones, and notebooks at the right moments.” This why C. S. Lewis can say about writing, “I don’t know what I mean till I see what I’ve said.” He has to fully articulate an idea before he can fully apprehend it—and that articulation requires an external aid.
Clark relates an exchange between physicist Richard Feynman and historian Charles Wiener that gets at the same point. Wiener observed that Feynman’s notes had been helpful to his work. No, corrected Feynman, they were the work.
“I actually did the work on the paper,” he said.
“Well,” Weiner responded, “the work was done in your head, but the record of it is still here.”
“No, it’s not a record, not really. It’s working. You have to work on paper and this is the paper. Okay?” Working on paper was an essential part of Feynman’s thinking process. His brain recruited paper and pencil into its predictive, problem-solving efforts. Without them, he couldn’t have done the work.
Our Tools Become Us
We don’t simply use our tools; to the extent they become a regular part of our mental kit, we absorb them. They become part of us. When I look at my home library, for instance, I’m actually seeing an external organ of my own thought. My books are in that sense part of my brain, my extended mind.
That goes for all the other tools of daily life: my smartphone, wrist watch, GPS, and more. At some point in the near future, it’ll also include generative AI, already finding its way into my workflows and thus my predictive process. At some point, that’ll be most of us—however we customize and modify its applications to our needs and reservations. At least, that’s my guess.
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My limited understanding of Jean Piaget’s constructivist theory of cognitive development suggests something very similar to what Clark is saying. From experience, we form ‘schemes’ or schema of what we perceive, then use them to make sense of the world, going through a constant process of adaptation and refinement. It is proactive and predictive as Clark describes. A small child with a pet dog will apply a ‘dog’ scheme to the next animal he sees with four legs and a tail. So for a brief period a cow will be a dog as he is actively processing and building upon the new experience. It’s a lifetime process of ‘disequilibrium’ as long as are open to new experiences.
This is really interesting! Might have to put the book on my TBR. I’m so fascinated by brain science and have been digging into a lot of the research around polyvagal theory and the autonomic nervous system. That idea that the brain uses sensory information to reinforce rather than generate ideas makes so much sense to me from a trauma perspective and matches with the work Stephen Porges has done. It explains why all the mindfulness of the current sensory input isn’t enough to overcome your mind if it’s already decided something is dangerous and is looking for reinforcement of that idea.