Abstract
Partially valid central cues have been extensively used to study the effects of spatial attention on visual performance. However, the effect of cue reliability has not been examined in great detail. We assessed the effects of cue reliability in motion discrimination and speeded detection tasks. Four random dots kinematograms (RDKs) were presented in the four visual quadrants at 10° eccentricity. Each RDK was contained within a circular aperture of 5° diameter. In the discrimination task, participants reported the direction of translational coherent motion. Coherent motion occurred in only one of the four apertures. Its likely location was indicated by a cue whose reliability varied across trials over 4 levels (25%, 60%, 75%, 86%). Discrimination accuracy was greater when motion stimuli were preceded by valid than invalid cues. This effect was modulated by cue reliability, the greater the cue reliability the greater the validity effect. Moreover, validity effects were also found in the 25% reliability condition, when no task relevant spatial information was provided by the cue. In the detection task, the set-up was the same, except that participants had to report the onset of expanding motion as quickly as possible, rather than motion direction. Validity and reliability effects were also found in this paradigm. We compared performance when two quadrants were cued either by a pro-cue (pointing to the location where coherent motion will have appeared) or anti-cue (pointing to locations where coherent motion will not have appeared). Anti-cues were associated with poorer performance than pro-cues. On the other hand, discrimination performance when one or two quadrants were cued, by cues which provided the same amount of spatial information, i.e. one bit, was virtually identical. We conclude that visual performance, following central cues, reflect both the utility of cued information as well as automatic processes.
A. Close is supported by an ESRC studentship.