Conspiracist Knowledge

Conspiracy theories can catalyse political violence, yet the literature tends to lump conspiracy-minded citizens into a single, undifferentiated category – as if there were only one way of being a conspiracist. We argue that a critical, omitted variable in the debate is conspiracist knowledge – the domain‑specific factual competence that equips citizens to navigate and legitimise stigmatized narratives. In this paper, we develop and validate a country-invariant four-item scale of multiple‑choice questions covering references such as MK‑Ultra and Project Blue Beam, both on an eight‑country pilot (N≈1,600) and on a quota sample of 20,000 adults after the 2024 elections. Our results show that conspiracist knowledge is highly selected, socially stratified, and concentrated in the United States and United Kingdom. Combining the index with a conspiracist-beliefs scale reveals a small but consequential minority of “informed believers” (≈ 10–25 %). Not only do they cluster at the polar ends of the left-right continuum, but they are markedly more willing than naive believers to condone political violence – evidence that deeper conspiracist knowledge travels with stronger ideological extremism. Conspiracist knowledge seems thus to operate as a behavioural multiplier, magnifying the mobilising force of conspiracist belief.