No abstract

Two priming experiments demonstrated exogenous attentional persistence to the fundamental auditory dimensions of frequency (Experiment 1) and time (Experiment 2). In a divided-attention task, participants responded to an independent dimension, the identification of three-tone sequence patterns, for both prime and probe stimuli. The stimuli were specifically designed to parallel the local-global hierarchical letter stimuli of [Navon D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353-383] and the task was designed to parallel subsequent work in visual attention using Navon stimuli [Robertson, L. C. (1996). Attentional persistence for features of hierarchical patterns. Journal of Experimental Psychology: General, 125, 227-249; Ward, L. M. (1982). Determinants of attention to local and global features of visual forms. Journal of Experimental Psychology: Human Perception and Performance, 8,[562][563][564][565][566][567][568][569][570][571][572][573][574][575][576][577][578][579][580][581]. The results are discussed in terms of previous work in auditory attention and previous approaches to auditory local-global processing.

No abstract

No abstract

Increased computer use in clinical settings offers an opportunity to develop new neuropsychological tests that exploit the control computers have over stimulus dimensions and timing. However, before adopting new tools, empirical validation is necessary. In the current study, our aims were twofold: to describe a computerized adaptive procedure with broad potential for neuropsychological investigations, and to demonstrate its implementation in testing for visual hemispatial neglect. Visual search results from adaptive psychophysical procedures are reported from 12 healthy individuals and 23 individuals with unilateral brain injury. Healthy individuals reveal spatially symmetric performance on adaptive search measures. In patients, psychophysical outcomes (as well as those from standard paper-and-pencil search tasks) reveal visual hemispatial neglect. Consistent with previous empirical studies of hemispatial neglect, lateralized impairments in adaptive conjunction search are greater than in adaptive feature search tasks. Furthermore, those with right hemisphere damage show greater lateralized deficits in conjunction search than do those with left hemisphere damage. We argue that adaptive tests, which automatically adjust to each individual's performance level, are efficient methods for both clinical evaluations and neuropsychological investigations and have the potential to detect subtle deficits even in chronic stages, when flagrant clinical signs have frequently resolved. (JINS, 2008, 14, 243-256.)

No abstract

Visual attention research has revealed that attentional allocation can occur in space-and/or objectbased coordinates. Using the direct and elegant design of R. Egly, J. Driver and R. , we examine whether space-and object-based inhibition of return (IOR) emerge under similar time courses. The present experiments were capable of isolating both space-and object-based effects induced by peripheral and back-to-center cues. They generally support the contention that spatially non-predictive cues are effective in producing space-based IOR at a variety of SOAs, and under a variety of stimulus conditions. Whether facilitatory or inhibitory in direction, the object-based effects occurred over a very different time course than did the space-based effects. Reliable object-based IOR was only found under limited conditions and was tied to the time since the most recent cue (peripheral or central). The finding that object-based effects are generally determined by SOA from the most recent cue may help to resolve discrepancies in the IOR literature. These findings also have implications for the search facilitator role IOR is purported to play in the guidance of visual attention.Considerable research has been dedicated to characterizing attentional allocation in visual displays. Among the many paradigms developed to investigate visual attention, the spatial cueing paradigm developed by Michael Posner (1980) has been instrumental in revealing many aspects of attentional allocation. In its most simple form, the cueing paradigm manipulates viewers' covert attention with a salient peripheral change (a cue) before they are asked to detect a target. By changing the spatial relationship between cue and target, i.e. whether they are spatially co-located or not, attentional effects can be measured through costs and benefits in response time (RT). This simple yet elegant procedure has been used to reveal two features of visual attention that are the focus of the present research: inhibition of return (IOR) and objectbased selection.Inhibition of return is one of two major reflexive attentional processes thought to contribute to detection differences at cued versus neutral 1 or uncued locations (Klein, 2000;Posner & Cohen, 1984). Inhibition of return is demonstrated by slowed RTs to cued target locations when compared to uncued target location RTs. In contrast, facilitation is revealed when detection at cued locations is speeded relative to uncued locations. The emergence of one effect or the other is typically linked to stimulus onset asynchrony (SOA) and/or the predictive value of the cue.Some investigators have argued that facilitation and inhibition reflect different attentional mechanisms, rather than two phases of one attentional system (e.g., Bao & Pöppel, 2006;Berger & Henik, 2000;Rafal & Henik, 1994; Correspondence should be sent to: Alexandra List, School of Psychology, Adeilad Brigantia, Penrallt Road, University of Wales, Bangor, Gwynedd LL57 2AS, United Kingdom, a.list@bangor.ac.uk. 1 In later experiments, the neutral ...

No abstract