Do conspiracy theories efficiently signal coalition membership? An experimental test using the "Who Said What?" design

Abstract

Theoretical work in evolutionary psychology have proposed that conspiracy theories may serve a coalitional function. Specifically, fringe and offensive statements such as conspiracy theories are expected to send a highly credible signal of coalition membership by clearly distinguishing the speaker's group from other groups. A key implication of this theory is that cognitive systems designed for alliance detection should intuitively interpret the endorsement of conspiracy theories as coalitional cues. To our knowledge, no previous studies have empirically investigated this claim. Taking the domain of environmental policy as our case, we examine the hypothesis that beliefs framed in a conspiratorial manner act as more efficient coalitional markers of environmental position than similar but non-conspiratorial beliefs. To test this prediction, quota sampled American participants (total N = 2462) completed two pre-registered Who-Said-What experiments where we measured if participants spontaneously categorize targets based on their environmental position, and if this categorization process is enhanced by the use of a conspiratorial frame. We find firm evidence that participants categorize by environmental position, but no evidence that the use of conspiratorial statements increases categorization strength and thus serves a coalitional function.

Fig 1. Illustration of experimental stimuli.

Each statement is composed of two sentences. The first one, here written in ordinary type, corresponds to an environmental position and is identical across conditions. The second sentence, here written in italics, corresponds to a justification of the environmental position that varies across conditions, being either framed as conspiratorial (treatment condition) or not (control condition). Statements were paired with target photos taken from the Center for Vital Longevity Face Database [28].

Fig 2. Categorization by race and environmental position when statements are framed either in a non-conspiratorial (control) or conspiratorial (treatment) form (N = 1147).

Only race categorization was significantly lowered by the use of a conspiratorial frame. The reported numbers are effect sizes (r). Error bars correspond to bootstrapped 95% confidence intervals.

Fig 3. Categorization by race and environmental position when statements are either framed in a non-conspiratorial form (control) or in a conspiratorial form aligned with environmental position (treatment) (N = 1195).

Both race environmental position categorization scores do not significantly differ across conditions. The reported numbers are effect sizes (r). Error bars correspond to bootstrapped 95% confidence intervals.