Hallucinations and auditory-verbal signal detection studies: A meta-analytic review

Auditory-verbal signal detection tasks (AV-SDTs) are used to study hallucinatory experiences (HEs) in clinical and nonclinical groups, assessing perceptual decision making under ambiguous auditory conditions. Existing findings suggest that HEs are associated with response biases. However, effects sizes and subgroup differences remain unclear. This meta-analysis synthesized findings to quantify associations between HEs and AV-SDT performance, testing differences within clinical and nonclinical populations. Systematic searches identified studies published between January 1985 and April 2025. Reference lists were screened and authors contacted. Eligible studies examined associations between hallucinations or hallucination-proneness and AV-SDT performance using between-group or correlational designs. Data comprising 1,391 participants were pooled from 5 clinical (210 patients), and 10 non-clinical (1,181 participants) studies. Moderate-to-large effects were found between HEs and response bias across aggregate (g = -0.56 [95% CI: -0.84, -0.28, p = .001]), clinical (g = -0.88 [95% CI: -1.58, -0.17, p = .026]), and nonclinical (g = -0.43 [95% CI: -0.74, -0.11, p = .013]) subgroup models. Perceptual sensitivity was reduced in nonclinical (g = -0.17 [95% CI: -0.28, -0.07, p = .004]), but not clinical (g = 0.37 [95% CI: -0.00, 0.75, p = .050]), hallucinating samples. HEs are consistently associated with a liberal response bias across populations. HEs in nonclinical samples were linked to reduced perceptual sensitivity although this was not supported in clinical groups, potentially due to limited data. Findings highlight methodological gaps in AV-SDT research, including variability in design and hallucination assessment, underscoring the need for standardized approaches to improve generalizability across studies.