title: Overconfidence across the psychosis continuum: a calibration approach.
abstract: An 'overconfidence in errors' bias has been consistently observed in people with schizophrenia relative to healthy controls, however, the bias is seldom found to be associated with delusional ideation. Using a more precise confidence-accuracy calibration measure of overconfidence, the present study aimed to explore whether the overconfidence bias is greater in people with higher delusional ideation.
  
  
  
  A sample of 25 participants with schizophrenia and 50 non-clinical controls (25 high- and 25 low-delusion-prone) completed 30 difficult trivia questions (accuracy <75%); 15 'half-scale' items required participants to indicate their level of confidence for accuracy, and the remaining 'confidence-range' items asked participants to provide lower/upper bounds in which they were 80% confident the true answer lay within.
  
  
  
  There was a trend towards higher overconfidence for half-scale items in the schizophrenia and high-delusion-prone groups, which reached statistical significance for confidence-range items. However, accuracy was particularly low in the two delusional groups and a significant negative correlation between clinical delusional scores and overconfidence was observed for half-scale items within the schizophrenia group. Evidence in support of an association between overconfidence and delusional ideation was therefore mixed.
  
  
  
  Inflated confidence-accuracy miscalibration for the two delusional groups may be better explained by their greater unawareness of their underperformance, rather than representing genuinely inflated overconfidence in errors.
authors.affiliation: a School of Psychology , Flinders University , Adelaide , Australia.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Balzan
authors.affiliation: b Department of Psychiatry , University of British Columbia , Vancouver , Canada.
authors.forename: Todd S
authors.initials: TS
authors.lastname: Woodward
authors.affiliation: c School of Psychology , University of Adelaide , Adelaide , Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Delfabbro
authors.affiliation: d Department of Psychiatry and Psychotherapy , University Medical Center Hamburg-Eppendorf , Hamburg , Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Moritz
mesh_terms: D000328:Adult; D002138:Calibration; D003071:Cognition / Q000502:physiology*; D003702:Delusions / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000523:psychology*; D012565:Schizophrenic Psychology; D013850:Thinking; D055815:Young Adult
keywords: Overconfidence; delusion-proneness; delusions; psychosis continuum; schizophrenia