All items consisted of 256-grayscale, 185-by-200 (width-by-height) pixel graphics in Personal Computer Exchange (PCX) format, which were foveally presented for 500 ms on a CRT monitor using a light gray background (NeuroScan, 1994). All stimuli were displayed within a dark gray rectangular frame with its inner dimensions matching the stimulus size. This frame served as fixation to minimize eye movements and was kept on the screen for the duration of a block sequence. Words were presented in black uppercase Arial font (0.95° vertical angle; 3.3 – 8.7° horizontal angle) over a medium gray background. Face photographs included backgrounds of varying gray shades thereby occupying the entire rectangle frame (8.4° vertical angle; 9.0° horizontal angle). A constant 2.5 s stimulus onset asynchrony was used for both tasks. Participants were instructed to respond to every stimulus as quickly and accurately as possible and that there would be no overlap between blocks for item repetitions. Responses were accepted from 200 ms post-stimulus onset until the next stimulus onset (2500 ms). The initial response hand assignment (i.e., left/right button press for old/new responses) was counterbalanced across participants and switched after four blocks, thereby systematically alternating response hand assignment within participants and across tasks.
