I've been reading about how rituals (performed right before a task) increase confidence and readiness for the task, and improve performance by "dulling the neural response to performance failure" (source), and that they work by triggering the placebo effect. This lead me to my question: what is the probability of a ritual to cause this positive effect on a randomly chosen person?
I didn't manage to find any statistics or useful numbers regarding what part of the population is receptive to placebo.