The experiment reported in this and the next chapter chiefly investigated two processes which I believe are amplified in the deluded psychotic: confirmation bias (the tendency to seek and accept data that confirm one's hypotheses at the expense of data that refute them) and creativity (as defined and assessed by tests of so-called 'divergent thinking'). I was criticallyinterested in the effect of arousal, or general state of alertness and energy mobilization, on these processes as the acute psychotic episode is at least in part a disorder of overarousal.