title: Bilateral and two-item advantage in subitizing.
abstract: Subitizing refers to people's ability to enumerate small sets of items fast and accurately. The present study examined if the speed and scope of subitizing is improved when the items to be enumerated are presented bilaterally across hemifields rather than unilaterally in a single hemifield. Such an effect, known as the bilateral field advantage, has been observed in a number of other visual tasks. A second aim was to examine whether the speed of subitizing could be explained by the speed it takes to detect the items to be enumerated, as simple reaction times to multiple stimuli are known to be faster than responses to individual items (known as the redundant target effect, RTE). The results revealed a bilateral field advantage even for enumerating two items. Moreover, the two item condition was the optimal subitizing condition - even enumerating one single item took longer - but this effect was not due to the RTE. In fact, the RTE negatively correlated with the speed of enumerating the same stimuli.
authors.affiliation: Department of Psychology, University of Turku, Finland; Centre for Cognitive Neuroscience, University of Turku, Finland. Electronic address: hmrail@utu.fi.
authors.forename: Henry
authors.initials: H
authors.lastname: Railo
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Attention; Bilateral field advantage; Redundant target effect; Subitizing