From a Wall Street Journal story by Matthew Hutson headlined “‘The Experience Machine’ Review: What the Brain Sees”:
In 1995, a construction worker landed on a 6-inch nail, piercing his boot. After emergency physicians injected him with sedatives and cut away his footwear, they discovered that the nail had slid between his toes. He had escaped bodily harm, contrary to his painful perception.
Andy Clark recounts this event in “The Experience Machine: How Our Minds Predict and Shape Reality” to show that what we see and feel is guided not only by immediate sensation in a “bottom-up” flow of information but also by belief and expectation—from the top down. This principle may be common knowledge, but Mr. Clark, a professor of cognitive philosophy at the University of Sussex in the U.K., offers a steady and amenable hand through its many manifestations, and adds a couple of twists.
He starts his tour with sensory illusions. Recall that in 2015 an image of a dress went viral on social media. In reality, the dress was blue and black, but to many it appeared white and gold. Research later revealed that seeing a white-and-gold dress was especially common among those who assumed that the dress was photographed underneath a shadow.
Expectations can cause illusions in our other senses, too. In one study, about a third of participants listening for “White Christmas” in white noise believed they could hear the song. In another study, 89% of college students said they had at some point mistakenly felt their phone buzzing in their pockets, what is known as “phantom vibration syndrome.”
Cognitive expectations don’t merely fabricate; they can also help to elucidate. In so-called Mooney images, a photo is reduced to a collection of black patches on a white background. At first the image appears abstract and undecipherable, until observers are told what’s there—a dalmatian, say—at which point many will suddenly see the image clearly. Expectations also help differentiate. A pair of ambiguous lines may be discerned as either a “13” or a “B,” depending on the context. What we see depends on what makes sense in the moment.
Emotions, too, are constructed by a confluence of processes. A racing heartbeat might tell you that you’re scared, until you consider that you just went for a jog. The brain is constantly balancing expectation with new information, to varying results. People with depression and anxiety, Mr. Clark tells us, often have trouble breaking habits of thought, getting stuck in ruts of painful rumination or fearful anticipation.
Autistic people can find it difficult integrating the onslaught of stimulation into abstract concepts, and compensate by imposing order on the world through repetitive behaviors and focused interests. Mr. Clark notes that there’s no ideal balance of bottom-up and top-down. Autistic people might miss some abstractions while noticing the details. Sound engineers want to pick up on background noise; cocktail-party attendees do not.
Almost every modern book on the mind agrees that thoughts shape experiences. Two elements distinguish Mr. Clark’s work. First, rather than saying that we experience incoming sensations guided by expectation, he says that what we experience is the top-down prediction of what’s happening, nudged by bottom-up perception. “A predictive brain is a kind of constantly running simulation of the world around us—or at least, the world as it matters to us,” he writes. “Incoming sensory information is used to keep the model honest.” Researchers in Mr. Clark’s camp refer to perception as a “controlled hallucination.”
Neurologically, the framework makes sense. In some parts of the brain, neural pathways that go from sensory organs to higher cognition are outnumbered by those going the other way. And it’s inefficient to attend to every sensory detail when you can work with a gist of what’s happening, especially when there’s no news. “Who in corporate HQ wants to know that Billie’s work proceeded exactly as expected?” Mr. Clark writes.
But it’s not quite clear whether the crediting of experience to one direction or the other, to a bottom-up or top-down process, makes much practical difference or is even possible. (At one point Mr. Clark embarks on an attempt to wave away the hard problem of why subjective experience exists at all.)
The second twist is Mr. Clark’s explanation of actions. We are “creatures whose percepts and actions all flow from a single source,” he writes. “That source is the ongoing attempt to minimize . . . prediction error as we go about our lives.” We move because the brain first predicts that we’ll move, and then wants to reduce the difference between that prediction and reality, and so we move. But Mr. Clark doesn’t present much concrete evidence for this claim, or help us make sense of its counterintuitive nature. And what does his theory buy us? We still need to explain why we predict we’ll do something.
Further, it feels unfalsifiable. Why not simply predict that we’ll lie in a dark room until we die of dehydration, then go do that, and save a lot of hassle? Ah, because we also seek surprises, Mr. Clark argues, because they teach us about the world and reduce surprises down the road. Fine, but I don’t see the minimization of prediction error as the be-all explanation of behavior, trumping innate commands to survive and reproduce.
In a chapter titled “Beyond the Naked Brain,” Mr. Clark examines an area he’s studied extensively and written about in books such as “Natural-Born Cyborgs” (2004): the “extended mind.” The idea is that the mind exists not only in the brain but extends to all of its cognitive augmentations, including notebooks, smartphones, and perhaps eventually artificial intelligence and augmented reality. It’s a neat philosophical idea, but it feels rehashed and out of place here. I’m also skeptical of the practical importance of where in space we draw the outlines of mind.
What can we do with the knowledge that expectation influences experience? Among other ideas, Mr. Clark suggests reinforcing positive portrayals of minorities to prevent police from disproportionately shooting black people. He proposes occasionally prescribing placebos for pain control. He notes that self-affirmation and reframing our thoughts can help reduce anxiety. Psychedelics can reset self-destructive expectations. Meditation can reduce rumination and anticipation. The experience machine, it turns out, is tunable.
Matthew Hutson is the author of “The 7 Laws of Magical Thinking: How Irrational Beliefs Keep Us Happy, Healthy, and Sane.”
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