Fig. 7.

Results for Experiment 3. (A) Performance (% correct answers) in the symmetry detection task with two, three and four colours. (B) Grand-average ERPs for two colour symmetry (red) and noise (blue), three colour symmetry (pink) and noise (light blue) and, four colour symmetry (dark red) and noise (cyan) conditions. (C) SPN difference waves (Symmetry–Noise) for each condition. Waveforms depict the average of electrodes PO7 and PO8. (D–F) Topographic difference map for two (D), three (E) and four (F) colours. Each topographic difference map shows the difference between symmetry and noise in the 200–600 ms time window. Black dots indicate the position of electrodes PO7 and PO8.