Table 2.
Stimuli, tasks and number of trials in each class for each subject in the unmasked paradigm. Stimulus set A comprises 9 images per category for upright faces and inverted faces; 20 images for houses; 45 images for tools; 200 for Mondrian patterns. Set B comprises 15 natural images for each category: faces (including upper half body), animals, landmarks, vehicles, flowers. Set A comprises grayscale photographs of upright and inverted faces (Ekman faces (Ekman and Friesen, 1976)) and houses, line drawings (tools) and digitally synthesized color images (Mondrian patterns). Set B comprises natural color photographs, downloaded from the internet. Images were scaled to have the same approximate size and contrast on screen. Tasks: CD, Change Detection task on the fixation cross; OB, One-Back task for the stimulus category. In each trial, subjects reported a change in the fixation cross (in the CD task) or a repetition of stimulus category (in the OB task) in a time window of duration 0.5 s or 1 s, respectively, plus a random interval uniformly distributed in [0,500] ms, immediately following stimulus offset. Following the termination of the response period, the next trial began immediately in CD sessions, or after the presentation of a feedback screen in OB sessions, which lasted 500 ms.
sub ID | Stimuli | # sessions (CD, OB) | U Face vs. Other | U vs. I Face |
---|---|---|---|---|
1471 | Face, Checkerboard | 2 | 320/80 | |
153 | Set A | 2,2 | 118/455 | 118/113 |
154a | Set A | 1,1 | 61/239 | 61/56 |
154b | Set A | 1,1 | 64/236 | 64/57 |
154 | Set A | 2,2 | 125/475 | 125/113 |
168 | Set A | 2,0 | 41/159 | 41/43 |
178 | Set B | 2,2 | 100/400 |
this subject performed gender and emotion discrimination tasks as described in (Tsuchiya et al., 2008); the number of trials indicated refer to a “face” vs. “checkerboard” decoding analysis. In the case of subject 154, the set of recorded electrodes differed across sessions: “154a” and “154b” indicate the sets of electrodes that were recorded in only a subset of the sessions (shown in Fig. S5), while “154” indicates the set of electrodes that were recorded in every session.