Participants were seated in a quiet, dimly-lit room, 1 m in front of a computer monitor on which the visual stimuli were presented. The visual stimuli consisted of a series of unilaterally-presented white squares on a black background. The squares (of visual angle 2×2 degrees) were presented for 82 ms on the horizontal meridian, with the inner edge of the squares 6.79 degrees lateral to a central fixation cross (see Figs. 1a and 1b). The fixation cross was continually present during each block of trials. On target trials, a red dot (0.82 degrees wide) was presented at fixation simultaneously with the lateral square (see Figs. 1c and 1d). Participants were instructed to maintain their gaze on the central fixation cross and count the number of targets they saw. There were 4 blocks of trials, each consisting of 30 left visual field (LVF) non-target trials, 30 right visual field (RVF) non-target trials, 8 LVF/target trials and 7 RVF/target trials, presented in pseudo-random order. Stimulus onset asynchrony was 624 ms. Each block took approximately 1 minute to complete. Participants’ data were not analyzed further if they missed 4 or more targets in one or more of the 4 blocks.
