Figure 1.

A schematic of the employed CPT-IP task is shown. The task alternated between two- and three-digit extended epochs and subjects were required to detect repeated presentation of numbers. As seen attention demand was modulated by manipulating figure-ground contrast. The numbers in the figure were RGB: 255, 255, 255; the ground was RGB: 225, 225, 225 in order to minimize contrast. In addition, font between successive numbers alternated (arial, times new roman). This ensured a baseline level of “flicker” between successive presentations, pre-empting target detection based on visual cues such as the absence of flicker.