title: Effects of age on searching for and enumerating targets that cannot be detected efficiently.
abstract: We investigated the effects of old age on search, subitizing, and counting of difficult-to-find targets. In Experiment 1, young and older adults enumerated targets (Os) with and without distractors (Qs). Without distractors, the usual subitization-counting function occurred in both groups, with the same subitization span of 3.3 items. Subitization disappeared with distractors; older adults were slowed more overall by their presence but enumeration rates were not slowed by ageing either with or without distractors. In contrast, search rates for a single target (O among Qs) were twice as slow for older as for young adults. Experiment 2 tested and ruled out one account of age-equivalent serial enumeration based on the need to subvocalize numbers as items are enumerated. Alternative explanations based on the specific task differences between detecting and enumerating stimuli are discussed.
authors.affiliation: Department of Psychology, University of Warwick, Coventry, UK. d.g.watson@warwick.ac.uk
authors.forename: Derrick G
authors.initials: DG
authors.lastname: Watson
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Maylor
authors.forename: Lucy A M
authors.initials: LA
authors.lastname: Bruce
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014796:Visual Perception