The Critical Thinking about Conspiracies (CTAC) Test: Development and Validation

How should we measure people’s vulnerability to unreasonable conspiracy theories? This is a key question for those designing interventions that aim to limit the spread of inaccurate beliefs. We argue that existing approaches are either too specific (measuring belief in a known conspiracy theory) or too general (measuring broad beliefs about the world). We developed the Critical Thinking about Conspiracies assessment (CTAC), where participants critically assess fictional conspiracies. In Study 1 (n =3341) we conducted several iterative pilot studies to develop the items. In Study 2 (n = 151) we conducted an exploratory factor analysis, reporting a two-factor solution, where the ability to correctly appraise implausible and plausible conspiracy theories are distinct but interrelated components. In Study 3 (n =106) we conducted a confirmatory factor analysis to assess the goodness of fit and demonstrated convergent validity. The CTAC has 8 items, can be easily administered online and takes approximately 5 minutes to complete.