FEATURE-SPECIFIC EFFECTS OF SELECTIVE VISUAL-ATTENTION

Four experiments were conducted to quantify the effect of performing a foveal discrimination task on sensitivity for a peripheral grating. T he observer's primary task was to discriminate either the spatial freq uency or orientation of successive foveal Gabor patches. On a third of the trials they also performed a secondary task to detect the presenc e of a near-threshold grating in the periphery. We find that sensitivi ty for detection of the peripheral grating depends on the similarity o f the spatial frequencies and orientations between the foveal and peri pheral stimuli. Importantly, sensitivity is also affected by which fea ture is being discriminated in the central task. Because the detectabi lity of the peripheral grating is different when different features of the central stimuli are discriminated, we suggest that the effects on sensitivity are due to feature-specific attention and not simply to p assive interactions between filters with similar tuning properties.