Mapping the spatiotemporal dynamics of interference between two visual targets.

A major thread of visual cognition has been to explore the characteristics of the attention system by presenting two targets and observing how well they can both be reported as a function of their temporal and spatial separation. This method has illuminated effects such as the attentional blink, the attentional dwell time, competitive interference, sparing temporal order errors, and localized attentional interference. However, these different effects are typically explored separately, using quite distinct experimental paradigms. In an effort to consolidate our understanding of these various effects into a more comprehensive theory of attention, we present a new method for measuring spatial gradients of interference at different temporal separations between two targets without creating specific expectations about target location. The observed data support theories that there are multiple sources of interference within the visual system. A theoretical model is proposed that illustrates how three distinct forms of interference could arise through the processes of identifying, attending, and encoding visual targets.