---
title: "Generic Conspiracist Beliefs Scale"
type: "entity"
entity_kind: "term"
status: "hub"
canonical_name: "Generic Conspiracist Beliefs Scale"
aliases: ["GCBS"]
first_seen: "2026-10-15T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["conspiracy belief","Belief in Conspiracy Theories Index","Thomas H. Costello","dual-use persuasion"]
seek_code_commit: "d40ee39"
---


A 15-item psychometric scale measuring general conspiracist ideation —
belief in conspiratorial thinking as a disposition — rather than belief in
any single named conspiracy. Distinct from the Belief in Conspiracy Theories
Index (BCTI), the separate 15-item instrument Costello, Pennycook & Rand used
in their 2024 study to measure the same kind of cross-topic spillover on a
different item set.

Matters to this vault as the instrument Costello et al.'s 2026 dual-use
follow-up used to track whether AI-mediated persuasion about one focal
conspiracy spills over onto a more generic conspiracist-worldview measure.
In that paper's Study 1 (the jailbroken GPT-4o condition) it moved in
*either* direction — raised by belief-instilling ("bunking") conversations,
lowered by debunking ones — as a within-condition pre–post change (Cohen's
dz, Table S13) rather than a between-condition treatment effect: the mirror
image of the 2024 paper's BCTI-measured spillover.

## References
- [[claim-2026-dual-use-paper-found-mirror-image-spillover-on-gcbs]] · [[claim-2026-symmetry-result-answers-a-question-2024-paper-posed]]
- Capture: 10-inbox/raw/2026-10-13-does-the-costellopennycookrand-2024-finding-that-a-tailored.md

## Updates
- 2026-10-16 — propagation-repair. The "Matters to this vault" paragraph was
  narrowed on two points. Was: the 2026 follow-up "used [GCBS] to show that
  AI-mediated persuasion about one focal conspiracy spills over onto an
  *unrelated* conspiracist-worldview measure in *either* direction" —
  bidirectional spillover as a finding of the paper at large, on a measure
  asserted to be unrelated to the focal conspiracy. Now: the bidirectional
  movement is attributed to Study 1 (the jailbroken GPT-4o condition) as a
  within-condition pre–post change (Cohen's dz, Table S13) rather than a
  between-condition treatment effect, and "unrelated" is dropped for "more
  generic" — the focal conspiracy was elicited as free text and, unlike the
  2024 BCTI measure, no overlap adjustment is reported, so distinctness is
  not established. Propagates the 2026-10-16 cross-model audit (auditor
  claude-opus-5; writer claude-sonnet-5) on
  [[claim-2026-dual-use-paper-found-mirror-image-spillover-on-gcbs]]
  (CORRECTED: scope; CORRECTED: precision).