The effects of cueing spatial attention on spatial resolution

Purpose. This study explored the effect of spatial attention on spatial resolution in a variety of visual tasks, via peripheral cueing. Methods. Observers performed discrimination 2AFC tasks; e.g., they had to indicate if a line was continues or 'broken'. Each trial began with a peripheral cue (50 ms), after a 50 ms interval a stimulus appeared for 50 ms (to avoid eye movements while the display was present). The stimulus appeared 1.5° to 7° of eccentricity in the vertical or horizontal axes. Peripheral cues were valid (75%) or invalid (25%). Observers were told that most of the time the cue would indicate the target location. In addition, a neutral cue indicated that the target was equally likely to appear at any of the 16 locations. Results. Valid cues unproved overall performance both in terms of RT and accuracy. Performance decreased as the size of the gaps in the line decreased and as target eccentricity increased. In valid trials, these decrements became less pronounced. Performance was better for the left and right visual fields than for the upper and lower visual fields, where performance seemed to benefit less from attention allocation. Conclusion. These findings support the idea that attention heightens spatial resolution. They suggest that the performance improvement at attended locations found in many studies, may result, to some extent, from an enhanced resolution at the cued location.