The Generic Conspiracist Beliefs Scale – 5: A short-form measure of conspiracist ideation

The Generic Conspiracist Beliefs Scale (GCB-15) is a reliable and valid measure of conspiracist ideation, but it is also inefficient. At 15 items, the GCB-15 can take upwards of four minutes to complete, limiting its usefulness in situations where administration time and participant attention are limited. Here we introduce the GCB-5—a 5-item, short form of the GCB-15. Across five studies, we demonstrate that the GCB-5 is both a reliable and valid measure of conspiracist ideation. With respect to its reliability, we find consistent evidence that a single latent factor underlies the GCB-5 and accounts for a sizeable proportion of the variation in its items. With respect to its validity, we show that the GCB-5 is associated with both self- and informant-report measures of conspiracist beliefs, as well as with a multitude of theoretically relevant constructs, including anomie, fatalism, and delusional ideation. In the final study, we provide evidence that the GCB-5 is not only a reliable and valid measure but also one that has promise for addressing novel research questions. Specifically, we show that people high in conspiracist ideation—as assessed by the GCB-5—are more accepting of the use of nuclear weapons and other forms of so-called “virtuous violence” (e.g., the death penalty; anti-abortion legislation).