title: Decision processes and the slowing of simple choices in schizophrenia.
abstract: Individuals diagnosed with schizophrenia have slowed response times (RT). We examined the role of decision processes in the slowing of simple choice responses. We updated Schatz's (1998) meta-analysis of deficits in speed and extend it to systematically examine the effects of schizophrenia on choice accuracy. We then report an experiment requiring decisions about motion direction, which we analyzed using an evidence accumulation model of choice, the linear ballistic accumulator (LBA; Brown & Heathcote, 2008). By simultaneously taking into account all aspects of behavior, the LBA was more sensitive to deficits than mean RT or accuracy alone. It also identified the 2 underlying causes of slowing: more cautious decisions (i.e., requiring more evidence before making a decision) and perceptual deficits. The schizophrenia group displayed strong sequential effects that were captured by the response on the previous trial affecting the relative amount of evidence required for choice in the LBA. These results illustrate that evidence accumulation models provide a sensitive tool that can be used to identify the cognitive mechanisms causing slowing in schizophrenia.
authors.affiliation: School of Psychology, University of Newcastle.
authors.forename: Andrew
authors.identifier: 0000-0003-4324-5537
authors.initials: A
authors.lastname: Heathcote
authors.affiliation: School of Psychology, University of Newcastle.
authors.forename: Anna
authors.initials: A
authors.lastname: Suraev
authors.affiliation: School of Psychology, University of Newcastle.
authors.forename: Samuel
authors.initials: S
authors.lastname: Curley
authors.affiliation: School of Psychology, University of Newcastle.
authors.forename: Qinchun
authors.initials: Q
authors.lastname: Gong
authors.affiliation: Department of Psychology, University of Amsterdam.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Love
authors.affiliation: School of Psychology, University of Newcastle.
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Michie
mesh_terms: D000328:Adult; D002755:Choice Behavior / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009039:Motion Perception / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D012565:Schizophrenic Psychology