Knowledge corruption for visual perception in individuals high on paranoia

Steffen Moritz*, Anja S. Göritz, Niels Van Quaquebeke, Christina Andreou, David Jungclaussen, Maarten J V Peters

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    17 Citations (Scopus)


    Studies revealed that patients with paranoid schizophrenia display overconfidence in errors for memory and social cognition tasks. The present investigation examined whether this pattern holds true for visual perception tasks.Nonclinical participants were recruited via an online panel. Individuals were asked to complete a questionnaire that included the Paranoia Checklist and were then presented with 24 blurry pictures; half contained a hidden object while the other half showed snowy (visual) noise. Participants were asked to state whether the visual items contained an object and how confident they were in their judgment. Data from 1966 individuals were included following a conservative selection process.Participants high on core paranoid symptoms showed a poor calibration of confidence for correct versus incorrect responses. In particular, participants high on paranoia displayed overconfidence in incorrect responses and demonstrated a 20% error rate for responses made with high confidence compared to a 12% error rate in participants with low paranoia scores. Interestingly, paranoia scores declined after performance of the task.For the first time, overconfidence in errors was demonstrated among individuals with high levels of paranoia using a visual perception task, tentatively suggesting it is a ubiquitous phenomenon. In view of the significant decline in paranoia across time, bias modification programs may incorporate items such as the one employed here to teach patients with clinical paranoia the fallibility of human cognition, which may foster subsequent symptom improvement.

    Original languageEnglish
    Pages (from-to)700-705
    Number of pages6
    JournalPsychiatry Research
    Issue number3
    Publication statusPublished - 30 Mar 2014


    • Confidence
    • Delusions
    • Depression
    • Knowledge corruption
    • Paranoia
    • Schizophrenia
    • Visual illusions


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