Abstract
Purpose: Discriminability across our visual field is heterogeneous. It is greatest at the fovea and diminishes with eccentricity. Perception also varies across isoeccentric locations with different polar angles, a phenomenon known as performance fields: perception is best at the horizontal meridian, worst at the upper vertical meridian, and intermediate at the lower vertical meridian. Spatial attention improves discriminability at different isoeccentric locations to the same degree, but it equates speed of processing, thereby preserving performance fields for discriminability but eliminating them for speed of processing. Here we asked whether temporal attention benefits performance in a similar or differential way across the visual field. Methods: Participants (n=8) discriminated the orientation of one of two grating patches presented serially at foveal or parafoveal (4° eccentricity) isoeccentric locations (right horizontal meridian and upper vertical meridian). Each target was tilted clockwise or counterclockwise about the vertical or horizontal axis independently of the other. Spatial location varied across sessions. Prior to stimulus presentation participants were pre-cued to attend to the first target (high tone), the second target (low tone), or both targets (both tones together; neutral cue). After presentation of the second target, a response cue instructed observers which target to discriminate, first or second, with equal probability on neutral trials. On valid trials, the response cue matched the pre-cue. Results: Temporal attention improved performance (d'), more so for the first than second target, and shortened RT to the same degree across all targets and locations. Critically, the magnitude of the attentional effect did not differ across spatial locations. Conclusion: Temporal attention benefited discriminability and shortened RT at foveal and different parafoveal locations equally, providing evidence that temporal attention is uniformly effective across the visual field. Performance fields are preserved with temporal orienting of attention.
Meeting abstract presented at VSS 2018