title: What does the object decision task measure? Reflections on the basis of evidence from semantic dementia.
abstract: The authors investigated the impact of semantic knowledge on visual object analysis by assessing the performance of patients with semantic dementia on a different-views object matching test and on 2 object decision tests differing, for example, in whether the nonreal items were nonsense objects or chimeras of 2 real objects. On average, the patients scored normally on both the object matching and the object decision test including nonsense objects but were impaired on the object decision test including chimeras; this latter was also the only visual object test that correlated significantly with degree of semantic impairment. These findings demonstrate that object decision is not a single task or ability and that it is not necessarily independent of conceptual knowledge.
authors.affiliation: Medical Research Council Cognition and Brain Sciences Unit, Cambridge, England.
authors.forename: Marjolijn
authors.initials: M
authors.lastname: Hovius
authors.forename: Marion L
authors.initials: ML
authors.lastname: Kellenbach
authors.forename: Kim S
authors.initials: KS
authors.lastname: Graham
authors.forename: John R
authors.initials: JR
authors.lastname: Hodges
authors.forename: Karalyn
authors.initials: K
authors.lastname: Patterson
mesh_terms: D000368:Aged; D001284:Atrophy; D003210:Concept Formation / Q000502:physiology; D003657:Decision Making / Q000502:physiology*; D003704:Dementia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology*; D004193:Discrimination Learning / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011594:Psychometrics; D012660:Semantics; D013702:Temporal Lobe / Q000473:pathology / Q000503:physiopathology