title: The relationship between working memory capacity and broad measures of cognitive ability in healthy adults and people with schizophrenia.
abstract: OBJECTIVE
  Working memory (WM) capacity, typically measured with cognitively complex span tasks, is correlated with higher order cognitive abilities in healthy adults. The goals of this study were to determine whether a more focused measure of visual WM storage capacity would show similar higher order ability correlations in healthy adults and in people with schizophrenia (PSZ), thereby demonstrating the importance of simple storage capacity; determine whether the illness alters the pattern of correlations across cognitive domains; and evaluate whether between-groups differences in WM capacity could account for the generalized cognitive impairment in PSZ.
  
  
  METHODS
  Ninety-nine PSZ and 77 healthy controls (HCs) completed a visual WM change-localization task, the Wechsler Abbreviated Scale of Intelligence (WASI), and the MATRICS Consensus Cognitive Battery (MCCB).
  
  
  RESULTS
  PSZ performed more poorly than HCs on all cognitive measures. The between-groups effect size for WM capacity was large (d = 1.11). WM robustly correlated with WASI and MCCB performance, with no significant differences in the magnitude or pattern of correlations across groups. When the groups were pooled, WM capacity correlated at r = .68 with MCCB composite score and at r = .56 with WASI estimated Full Scale IQ. WM capacity accounted for approximately 40% of the between-groups variance across the WASI and MCCB.
  
  
  CONCLUSIONS
  A simple measure of WM storage capacity is robustly associated with the higher order cognitive abilities assessed by the WASI and MCCB in HCs and PSZ. WM capacity reduction may be a critical determinant of the general cognitive impairment in PSZ.
authors.affiliation: Baltimore VA Mental Health Care System, Mental Illness Research, Education & Clinical Center (VA Capital Health Care Network), Baltimore, Maryland, USA.
authors.forename: Melissa K
authors.initials: MK
authors.lastname: Johnson
authors.forename: Robert P
authors.initials: RP
authors.lastname: McMahon
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Robinson
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Harvey
authors.forename: Britta
authors.initials: B
authors.lastname: Hahn
authors.forename: Carly J
authors.initials: CJ
authors.lastname: Leonard
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Luck
authors.forename: James M
authors.initials: JM
authors.lastname: Gold
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000209:etiology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000150:complications*; D012565:Schizophrenic Psychology; D013223:Statistics as Topic; D013997:Time Factors; D055815:Young Adult