I think this is saying that microdosing is mainly placebo effect, and otherwise doesn’t do much. This makes sense. All these participants took full dose psychedelics at some point, and thus had very strong associations.
So far, as far as I know, that seems to be the prevailing scientific opinion, i.e. microdosing seems to be about as effective as placebo (at least microdosing of psilocybin).
I think the point of differentiating between the blinded and unblinded groups was to show that placebo alone does not account for the effects of microdosing.
