There are a number of competing psychological accounts of the placebo effect, and much of the recent debate centers on the relative importance of classical conditioning and conscious beliefs. In this paper, I discuss apparent problems with these accounts and with “disjunctive”
accounts that deny that placebo effects can be given a unified psychological explanation. The fact that some placebo effects seem to be mediated by cognitive states with content that is consciously inaccessible and inferentially isolated from a subject's beliefs motivates an account of the
placebo effect in terms of subdoxastic cognitive states. I propose that aliefs, subdoxastic cognitive states that are associative, automatic, and arational, can provide a unified psychological account of the placebo effect. This account also has the potential to illuminate interesting connections
to other psychological phenomena.