The Combination of Two Conspiracy-Belief-Scales and a correlational analysis with Epistemic Beliefs

Abstract

Abstract Conspiracy belief (CB) describes the extent to which the individual believes a conspiracy narrative. Conspiracy narratives represent anti-empirical theories according to which a minority has secretly come together to pursue sometimes vile goals with sometimes vile means. Over the last decade the scientific interest in CBs increased which led to many different scales to assess CBs. Often CB is measured using the acceptance of different conspiracy theories (CTs) expressed on a dichotomous or Likert scale. The aim of this study is to test the psychometric quality of two of the few validated scales for measuring CB in German-speaking countries and to maximise the validity of the questionnaires based on a test theory. A sample of N = 254 was recruited for this purpose. As a factorial analysis based on the classical test theory showed insufficient results, the item response theory and a graphical item threshold analysis was conducted indicated a dichotomous scale as most informative. As both the GVT-12 scale (Neumann, 2010) and the subscale real CT of van Prooijen et al. (2018) measured the acceptance of real CTs they were merged and jointly examined. The successive exclusion of items with unacceptable fit resulted in two scales, one for real CB and one for fictional CB, which only comprised van Prooijen´s items. As factor analysis was conducted to test the convergence of both scales. The results indicated a two-factorial model as best fitting. However, future studies should investigate a possible bifactorial structure. Moreover, the construct validity of both subscales was assessed through their correlation with epistemological beliefs, supporting the discriminant validity between fictional and real CB.