A paradigm for the study of paranoia in the general population: The Prisoner's Dilemma Game

Abstract

A growing body of research shows that paranoia is common in the general population. We report three studies that examined the Prisoner's Dilemma Game (PDG) as a paradigm for evaluation of non-clinical paranoia. The PDG captures three key qualities that are at the heart of paranoia—it is interpersonal, it concerns threat, and it concerns the perception of others' intentions towards the self. Study 1 (n=175) found that state paranoia was positively associated with selection of the competitive PDG choice. Study 2 (n=111) found that this association was significant only when participants believed they were playing the PDG against another person, and not when playing against a computer. This finding underscores the interpersonal nature of paranoia and the concomitant necessity of studying paranoia in interpersonal context. In Study 3 (n=152), we assessed both trait and state paranoia, and differentiated between distrust- and greed-based competition. Both trait and state paranoia were positively associated with distrust-based competition (but not with greed-based competition). Crucially, we found that the association between trait paranoia and distrust-based competition was fully mediated by state paranoia. The PDG is a promising paradigm for the study of non-clinical paranoia.