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According to the new theory (called “predictive processing”), reality as we experience it is built from our own predictions.
Predictive processing speaks to one of the most challenging questions in science and philosophy—the nature of the relationship between our minds and reality.
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.
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.
We can no more experience the world “prediction and expectation free” than we could surf without a wave.
The illusion occurred because predictive brains are guessing machines, proactively anticipating signals from the body and the surrounding world. That guessing is only as good as the assumptions it makes, and even a well-informed best guess will frequently miss the mark.
When the brain’s best guessing misses the mark, the mismatch with the actual sensory signal carries crucial new information. That information (prediction error) can be used to try again—to make a better guess at how things really are. But experience still reflects the brain’s current best guessing. It is just that each new round of guessing is a little bit better informed.
Instead, all human experience arises at the meeting point of informed predictions and sensory stimulations.
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.
Predictions and prediction errors are increasingly recognized as the core currency of the human brain, and it is in their shifting balances that all human experience takes shape.
With the prediction machinery up and running, perception becomes a process structured not simply by incoming sensory information but by difference—the difference between the actual sensory signals and the ones the brain was expecting to encounter.
In other words, the brain is constantly painting a picture, and the role of the sensory information is mostly to nudge the brushstrokes when they fail to match up with the incoming evidence.
This means that we can, at times, change how we feel by changing what we (consciously or unconsciously) predict. This does not mean we can simply “predict ourselves better,” nor does it mean we can alter our own experiences of pain or hunger in any way we choose.
This is the brain doing what it does best, churning out “good hallucinations” by filling in and fleshing out the missing signal according to what it expects to hear.
All human experience, if predictive processing is on track, is built in this way. We see the world by predicting the world. But where prediction errors ensue, the brain must predict again.
news—deviations from what is expected. This is efficient. Valuable bandwidth is not used sending well-predicted stuff upward.
Similarly in the neural incarnation, prediction errors at every level signal only the unexpected, the stuff that may plausibly demand further thought or action.
The feeling of “being in the zone” in sports reflects unexpectedly good error dynamics of this kind.
Being natively attracted to environments in which greater than expected amounts of prediction error are resolved is a neat way of ensuring adaptively beneficial tendencies toward play, learning, and exploration. Such creatures cannot help but seek out and prefer those parts of their world in which useful learning is currently possible. They are not at all attracted to those darkened rooms with their fully—and boringly—predictable profiles. Instead, they will constantly seek out richer environments on the edge of their current knowledge and abilities.
large and convincing studies that statistically combine the results reported by multiple experiments find no neat, recurrent “bodily fingerprints” for the different emotional states we seem to experience. There is no single set of bodily responses that is unique to sadness, or shame, or any of the many emotional states we name in daily life. Instead, emotional experience seems to be constructed, moment by moment, from a mixture of cultural influences, evidence and expectations about my current situation and my own current bodily states, and my own idiosyncratic tendencies (“individual
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what so often seem to us to be raw feelings or emotions are in fact already highly informed guesses about how things are: guesses that are based (even though we are seldom aware of this fact) on a surprisingly wide range of evidence, expectation, and information.
Overweighted expectations and underweighted new information would result in a kind of permanent or semipermanent lock-in of the existing model, leading us to continue with depressive behaviors that actually serve to reinforce the bad model, and that lend false justification to our prior expectations.
According to what has become known as the “salience detection hypothesis,” these chills occur when we encounter something that our brain identifies as critical new information that resolves important uncertainties. This makes it a kind of physiological echo of the “aha” moment when things suddenly fall into place.
Music is one of the most reliable causes of aesthetic chills.
why do we feel the chill that (in effect) says we have resolved a whole lot of dangling uncertainty when listening to a piece of music, or viewing a piece of theater, that we have experienced many times in the past? A full treatment of this would take us too far afield, but the key idea is that the power of great music (and great literature) lies in its ability to lead us through a staged process that first reliably builds up and then reliably resolves expectations.
probability designs”: artifacts engineered to interact in reliable ways with our own predictive brains. Books, novels, plays, and movies are all probability designs. Attention (precision-weighting) plausibly plays a key role here, adding impact to the musical items that portend key moments in the movement or symphony. Aesthetic chills are a physiological marker of this sudden increase in estimated importance (precision).
Emotion—or so we argued—reflects the changing value of different actions given our bodily state, goals, needs, and projects. It is a kind of marker of our embodied attunement (or lack of it) to the world.
Creatures like that will certainly appear sentient. They will respond to their worlds in ways informed by a delicate dance between what they detect in the external world and their own ever-changing bodily needs and states. This, I argue, is what underlies all the behavioral manifestations of “sentience.” We detect sentience in creatures (and potentially in robots) whose take on the external world is subtly but pervasively responsive to their brain or control system’s take on their own inner, bodily worlds and their own states of action readiness.
Inaccurate and “coarse” information that is wrongly estimated to be both informative and precise will rapidly lead predictive minds to confident but misguided conclusions. By improving our own interoceptive accuracy by means of biofeedback training, it may be possible to minimize or avoid these kinds of mistaken inference, allowing individuals to contextualize their own bodily responses in more helpful ways.
perception is more like painting than some kind of point-and-shoot photography—it is an act of creation that draws upon our own needs and history.
Predictions, anticipating the future and permeated with the past, shape human experience in all its forms.
University of Sussex colleague Professor Anil Seth sums this up quoting Anaïs Nin, “We do not see things as they are, we see them as we are.”
But even the simple pencil provides a stable, robust, real-time responsive means of offloading key intermediate results of processing onto a notepad, a loop we can repeat again and again as we build up more and more complex thoughts and ideas.
strategies emerge directly from the attempt to minimize a quantity known as expected future prediction error.
That writing down is not simply leaving a record, but part of the actual process of thinking things through.
The correct response to the worry is thus to firmly distinguish the process of recruitment (the selection of the right resources at the right time) from problem solving that then relies upon the recruited array of resources.
consider that prickly rush of adrenaline so often felt before going onstage or delivering a speech. We can practice attending to that feeling while verbally reframing it as a sign of our own chemical readiness to deliver a good performance.
For as we have seen, brains like ours are designed to minimize their own present and future errors in prediction. The more unpredictable the environment, the less error gets minimized, often resulting in anxiety, stress, and feelings of loss of control. Yet there is Hawkins, joyfully adding huge doses of the unexpected into his life.
It was probably this higher-level kind of predictability that kept him feeling safe and sane, and that enabled him to gain so much from his experiment. Even when we engineer our worlds to deliver surprise and enable learning, we do so in ways that limit surprise itself in mostly predictable ways—just
Aldous Huxley, in this 1954 account, The Doors of Perception, put it like this: To be shaken out of the ruts of ordinary perception, to be shown for a few timeless hours the outer and inner world, not as they appear to an animal obsessed with survival or to a human being obsessed with words and notions…this is an experience of inestimable value.
Seminal neuroimaging (fMRI) work by Carhart-Harris and colleagues has also shown that the changes in conscious experience that psychedelics promote are associated with decreases, rather than increases, of brain activity—something that, I strongly suspect, would have shocked Huxley with his image of (essentially) opening the floodgates.
Most excitingly, it offers the first fully unified treatment of perception and action. It displays them as co-constructed around the common goal of minimizing error in the prediction of sensory states. 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. These are complementary means of dealing with prediction error, and they work together, each constantly influencing and being influenced by the other.
at last embracing the fundamental unity of mind, body, and world. The shape of that unity is now clear. There is a fundamental drive, instantiated by the brain, to minimize errors in our own sensory predictions. That same drive guides, and is guided by, our own internal bodily states and by a rich array of physical actions, many of them designed to gather information and reduce uncertainty. Brain structure and neurochemistry, the physiological body, our own actions, history, and practices, and the environmental settings in which we live and work, all combine and cooperate to manage the flow of
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Thus understood, 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.
