Attention is less a lens on the world than a mirror for the mind. “My experience is what I agree to attend to,” William James wrote in his foundational treatise on attention in the final years of the nineteenth century. In the epoch since, we have discovered just what an “intentional, unapologetic discriminator” attention is, just how much it shapes our entire experience of reality. But we are only just beginning to discover that, far from a passive observer of the outside world, our attention is an active creator of it as the brain makes constant conscious and unconscious predictions of what it expects to find when it looks, then finds just that; we are only beginning to understand how right Thoreau was when, in James’s epoch, he observed that “we hear and apprehend only what we already half know.”

That is what cognitive philosopher Andy Clark explores in The Experience Machine: How Our Minds Predict and Shape Reality (public library) — an illuminating investigation of the human brain as a prediction machine that evolved to render reality as a composite of sensory input and prior expectation, replete with implications for neuroscience, psychology, medicine, mental health, neurodiversity, the relationship between the body and the self, and the way we live our lives.

Clark writes:

Contrary to the standard belief that our senses are a kind of passive window onto the world, what is emerging is a picture of an ever-active brain that is always striving to predict what the world might currently have to offer. Those predictions then structure and shape the whole of human experience, from the way we interpret a person’s facial expression, to our feelings of pain, to our plans for an outing to the cinema.

Nothing we do or experience — if the theory is on track — is untouched by our own expectations. Instead, there is a constant give-and-take in which what we experience reflects not just what the world is currently telling us, but what we — consciously or nonconsciously — were expecting it to be telling us. One consequence of this is that we are never simply seeing what’s “really there,” stripped bare of our own anticipations or insulated from our own past experiences. Instead, all human experience is part phantom — the product of deep-set predictions.

Because these predictions are informed by our past experience, reality is not how the present self parses the world but how the Russian nesting doll of selves we carry — all the people we have ever been, with all the experiences we have ever had — constructs the world before its eyes. Our sensorium is a simulation we ourselves are constantly running. Clark traces this predictive process as it unfolds at the meeting point of stimulus and expectation:

Incoming sensory signals help correct errors in prediction, but the predictions are in the driver’s seat now. This means that what we perceive today is deeply rooted in what we experienced yesterday, and all the days before that. Every aspect of our daily experience comes to us filtered by hidden webs of prediction — the brain’s best expectations rooted in our own past histories.

[…]

When the brain strongly predicts a certain sight, a sound, or a feeling, that prediction plays a role in shaping what we seem to see, hear, or feel.

Emotion, mood, and even planning are all based in predictions too. Depression, anxiety, and fatigue all reflect alterations to the hidden predictions that shape our experience. Alter those predictions (for example, by “reframing” a situation using different words) and our experience itself alters.

At the heart of this equivalence is the recognition that changing our expectations changes our experience — not in a New Age way, but in a neurocognitive way. With an eye to the opportunity to “hack our own predictive minds,” which Bruce Lee intuited in his insistence that “you will never get any more out of life than you expect,” Clark observes:

Since experience is always shaped by our own expectations, there is an opportunity to improve our lives by altering some of those expectations, and the confidence with which they are held.

Both the nature of our expectations and the confidence with which we hold them are shaped by a constellation of biological and psychological factors, from brain structure and neurochemistry to environment and personal history. Leaning on a large body of research, Clark examines how the brain’s unconscious compulsion for informed prediction shapes everything from our most basic sensations of heat and pain to our most complex experiences of selfhood and transcendence, revealing our brains to be not passive receptors of reality but “buzzing proactive systems that constantly anticipate signals from the body and from the world.” He writes:

To perceive is to find the predictions that best fit the sensory evidence. To act is to alter the world to bring it into line with some of those predictions… It is this deep reciprocity between prediction and action that positions predictive brains as the perfect internal organs for the creation of extended minds — minds enhanced and augmented by the use of tools, technologies, and the complex social worlds in which we live and work. Extended minds are possible because predictive brains automatically seek out actions that will improve our states of information, reducing uncertainty as we approach our goals (highly predicted future states). When such actions become parts of habit systems that call upon resources that are robustly available, trusted, and fully woven into our daily ways of dealing with the world, we become creatures whose effective cognitive apparatus exceeds that of the biological brain alone.

Emanating from the mind’s powerful predictive faculty is the haunting inevitability of personal responsibility for shaping our own experience. Centuries after Milton admonished in Paradise Lost that “the mind is its own place, and in it self can make a Heav’n of Hell, a Hell of Heav’n,” Clark writes in a sentiment of especial poignancy in the context of our present reckoning with consciousness and artificial intelligence:

Human minds are not elusive, ghostly inner things. They are seething, swirling oceans of prediction, continuously orchestrated by brain, body, and world. We should be careful what kinds of material, digital, and social worlds we build, because in building those worlds we are building our own minds too.

In the remainder of The Experience Machine, Clark goes on to explore how conscious expectations and unconscious predictions impact human experiences as varied as chronic pain and psychosis, and what we can do to hack this cognitive compulsion in order to ameliorate our suffering and magnify our vitality. Complement it with the fascinating science of the extended mind, then revisit Mary Oliver on what attention really means and Iris Murdoch on how it unmasks the universe.