Comparison of Auditory Spatial Attention Gradients in Sustained and Shifting Attention Tasks
In the visual modality it has been well documented that spatial attentional benefits decrease as a function of distance from an attended location, resulting in a linear attention gradient. A similar linear gradient is sometimes observed in the auditory modality, but recent findings suggest auditory attention gradients may be quadratic under at least some conditions. This project tested the hypothesis that linear auditory attention gradients are seen when the attended location is cued to change every few seconds, whereas quadratic gradients are observed when attention is sustained to a fixed location. Young adults completed a speeded sound discrimination task within a Posner like cue-target paradigm, in either a sustained or shifting attention condition. Subjects were repeatedly cued to the same location (sustained condition) or to a location that changed every few seconds (shifting condition). Following each cue, subjects made speeded responses to a white noise burst that was presented either at the cued location or 45°, 90°, 135°, or 180° away from the cued location. Reaction time results show similar quadratic auditory attention gradients for sustained and shifting attention conditions. Accuracy results show differences for attention conditions only when shifting attention to nearby locations. These results suggest the interaction of two auditory attention systems: a top-down auditory attention system which provides attention benefits to locations being consciously attended to, and a bottom-up attention system which serves to monitor spatial areas not being consciously attended to.