mediation

When something travels through a middle to get from cause to effect — the middle carries the signal, and the question is whether the road runs through it or past it.

A child who gets better at reading because practice builds vocabulary, and vocabulary then makes the text easier — vocabulary is the mediator: the cause (practice) reaches the effect (reading skill) through it. The statistical test asks whether the cause still moves the effect once the middle is held still; if it does not, the middle was the road. The castle uses the word where a therapy moves a trait and the trait moves a symptom — the trait is the mediator, and the question is whether the therapy's effect travels through the trait or alongside it.

The castle's rooms that lean on it: openness-or-anxiety-first asks whether openness change mediates symptom change in CBT the way it did in MDMA therapy, and pharmacological-or-cognitive asks whether the mediator is pharmacological or cognitive — whether the same trait opens through chemistry or through trained habit.