Lisa Feldman Barrett: Most Replayed Moment: Anxiety Is Just A Prediction! Rewrite Old Stories and Build Emotional Safety

The host opens by saying they learned the idea of the predictive brain from the guest and asks what it does and does not mean. The guest starts with how things feel. In ordinary life, including the conversation they are having, both people experience themselves as sensing what is said and then reacting to it. The guest says this is how most people experience the world, but it is not what is happening under the hood.

Really what's happening is that your brain is not reacting, it's predicting.

The guest asks the listener to imagine freezing time. At that instant the brain is in a particular state, and it is remembering past experiences similar to that state in order to predict what to do in the next moment. The predictions are about the body: whether the eyes should move, whether heart rate should rise, whether breathing should change, whether blood vessels should dilate or constrict, and whether to prepare to stand. The guest adds that copies of these movement-preparation signals become predictions for what a person will see, hear, smell, taste, think and feel. Experience, on this account, follows from the movements the brain is preparing.

You don't sense and then react, you predict action and then you sense.

Asked for an example, the guest points to the conversation itself. After a huge number of repetitions of listening to language, the host's brain is predicting every word the guest will say. The guest shows this by stopping mid-sentence before the word "mouth". They then note how surprising it would have been to name a different orifice, because the brain had already predicted the word. In the guest's words, the brain is always predicting and correcting those predictions when they are wrong.

The guest says they often show a video in talks to scientists and to "civilians" so audiences can feel that a prediction is more than an abstract thought. The claim is that the brain changes the firing of its own sensory neurons to anticipate incoming sensations, so people start to have an experience before the signals from the world arrive. The video itself is not described in this excerpt.

The host brings up thirst, which they recall reading about, possibly in the guest's book. The guest explains that a very thirsty person who drinks a big glass of water feels relief almost immediately.

But actually it takes 20 minutes for that water to be absorbed into your bloodstream and make its way to the brain to tell the brain that you are no longer in need of fluid.

The guest attributes the early relief to learning "across millions of opportunities" that certain movements and sensory signals now will lead to that mental state later.

Next the guest runs a live exercise. The host keeps their eyes on the guest and imagines a Macintosh apple, the fruit rather than the computer. The host says the apple they pictured has no red, and the guest concludes it is a Granny Smith. Imagining a bite and the crunch, the host describes it as sweet, maybe a little tart, and juicy. The guest says that if they were imaging the host's brain, they would see changes in activity in the visual cortex even with no apple present, and in the auditory cortex even though no crunch was heard. This is described as a hypothetical; no scan was done. The host adds that their mouth was watering.

The guest extends the point to meals. Each time a person sits down to eat, the brain directs the saliva glands to produce more saliva, usually before the person even sits down. The guest calls all of this prediction and makes a general efficiency claim.

predicting and correcting is a much more efficient way to run a nervous system, really any system, than reacting to the world.