https://astralcodexten.substack.com/p/the-precision-of-sensory-evidence

 

In earlier posts, I've expressed confusion about two competing models of depression. In one - supported by an analogy to mania and various forms of sensory and motor disturbance - it's inappropriately low neural confidence levels. In the other - supported by common sense - it's a highly-confident global prior on negative perceptions and events - a bias to interpret incoming information in a threat-related way. Both of these models had a lot going for them. But they didn't really fit together. Van der Bergh et al’s Better Safe Than Sorry: A Common Signature Of General Vulnerability For Psychopathology, in the October issue of Perspectives In Psychological Science, tries to tie the pieces together into a more ambitious theory of negative emotionality, including depression, anxiety and trauma.

Its solution is that these conditions are marked by a processing style that assigns unusually low precision to sensory evidence. All perception and cognition is the combination of evidence and priors. But in depression and otherwise neurotic people, the evidence is only a weak signal and the priors are a much stronger one.