Just as we perceive the outside world on the basis of sensory signals met with a top-down flow of perceptual expectations and predictions, the same a… - Sam Harris

" "

Just as we perceive the outside world on the basis of sensory signals met with a top-down flow of perceptual expectations and predictions, the same applies to perceptions of the internal state of the body. The brain has to know what the internal state of the body is like. It doesn’t have direct access to it, even though both the brain and body happen to be wrapped within a single layer of skin. As with perception of the outside world, all the brain gets from the inside of the body are noisy, ambiguous electrical signals. Therefore it has to bring to bear predictions and expectations in order to make sense of the barrage of sensory signals coming from inside the body, in just the same way as for vision and all the other “classic” senses. And this is what’s collectively called interoception — perception of the body from within. The same computational principles apply. In this view, we can think of emotional conscious experiences, feeling states, in the framework of “interoceptive inference.” So emotions become predictions — “best guesses” — about the hidden causes of interoceptive signals, in the same way that experiences of the outside world are constituted by predictions of the causes of sensory signals.
This gives a nice computational and mechanistic gloss to old theories of emotion that originated with William James and Karl Lange — that emotion has to do with perception of physiological change in the body and by the subsequent cognitive “appraisal” of these changes. The predictive-processing view adds to these theories by saying that emotional experience is the joint content of predictions about the causes of interoceptive signals at all levels of abstraction.