Fig. 3
Experimental design and datasets summary. (a) Overview of the experimental paradigm, showing two example blocks of trials: At any moment, no more than one high-contrast stimulus was present at fixation. In each trial, participants were asked to detect target stimuli: either a face and an object or a letter and a false font in any of the three different orientations. Thus, each trial contained three stimuli types: targets (depicted in orange), task-relevant stimuli (belonging to the same categories as the targets, depicted in yellow), and task-irrelevant stimuli (belonging to the two other categories, depicted in purple). Colored frames are used here for illustration purposes only and did not appear in the experiment. The pictorial stimuli (faces/objects) were task-relevant in half of the blocks (upper row), while the symbolic stimuli (letters/false fonts) were relevant in the other half of the blocks (lower row), and vice versa. Blank intervals between stimuli were also included but are not depicted here. (b) The stimulus properties we manipulated were category (objects, faces, letters and false fonts), identity (each category contained 20 different exemplars), orientation (left, right, and front view), and duration (0.5, 1.0, and 1.5 seconds). Example stimuli used in the study are shown here; for the full stimulus set see here. (c) Distribution of behavioral sensitivity scores (d’) separate for each of the three data acquisition sites. Horizontal black lines depict average d’ per site, and dots depict individual participants’ d’s. Average accuracy: M = 95.52 (SD = 7.58). Average reaction time (RT): M = 0.64 s (SD = 0.14). (d) Average fixation (Eyelink)/gaze coordinates (Tobii) heat maps computed over a 0.5 s window after stimulus onset, zoomed into the stimulus area for each recording site.
