Spatial attention improves performance in spatial resolution tasks

This study used peripheral precueing to explore the effect of covert transi ent attention on performance in spatial resolution tasks. Experiments 1 (La ndolt-square) and 2 ('broken-line') measured gap resolution and Experiment 3 measured vernier resolution In all three tasks the target was presented a lone in a large number of possible locations, ranging from 1.5-6 degrees of eccentricity in the vertical or horizontal axes. The precue indicated the target location but did not convey information regarding the correct respon se. Performance decreased as the gap size or the vernier offset size decrea sed and as target eccentricity increased. Precueing improved performance in terms of RT and accuracy in all three tasks; the eccentricity effect decre ased in the cued trials of the gap resolution tasks. These findings support the idea that the performance improvement at attended locations results, t o some extent, from an enhanced spatial resolution at the cued location, an d not just from distracter exclusion, diminished uncertainty, or decisional factors. (C) 1998 Elsevier Science Ltd. All rights reserved.