Jumping to conclusions about the beads task? A meta-analysis of delusional ideation and data-gathering

Robert Malcolm Ross*, Ryan McKay, Max Coltheart, Robyn Langdon

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    135 Citations (Scopus)


    It has been claimed that delusional and delusion-prone individuals have a tendency to gather less data before forming beliefs. Most of the evidence for this "jumping to conclusions" (JTC) bias comes from studies using the "beads task" data-gathering paradigm. However, the evidence for the JTC bias is mixed. We conducted a random-effects meta-analysis of individual participant data from 38 clinical and nonclinical samples (n = 2,237) to investigate the relationship between data gathering in the beads task (using the "draws to decision" measure) and delusional ideation (as indexed by the "Peters et al Delusions Inventory"; PDI). We found that delusional ideation is negatively associated with data gathering (rs = -0.10, 95% CI [-0.17, -0.03]) and that there is heterogeneity in the estimated effect sizes (Q-stat P = .03, I2 = 33). Subgroup analysis revealed that the negative association is present when considering the 23 samples (n = 1,754) from the large general population subgroup alone (rs = -0.10, 95% CI [-0.18, -0.02]) but not when considering the 8 samples (n = 262) from the small current delusions subgroup alone (rs = -0.12, 95% CI [-0.31, 0.07]). These results provide some provisional support for continuum theories of psychosis and cognitive models that implicate the JTC bias in the formation and maintenance of delusions.

    Original languageEnglish
    Pages (from-to)1183-1191
    Number of pages9
    JournalSchizophrenia Bulletin
    Issue number5
    Publication statusPublished - Sept 2015


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