MVPA results
MVPA analyses showed that neural activity between the small and large choice sets began to differ 128 ms after stimulus onset and persisted until 1500 ms (p < 0.001, cluster-based correction;Fig. 4A ). Temporal generalization matrices indicated that neural activity between the small and large choice sets during these time periods (training time = [128,1488], testing time = [108, 1488], p < 0.001; Fig. 4B ) could be predicted from one another. As depicted in the activation maps inFig. 4C , the posterior electrodes exhibited activation (p < 0.001, cluster-based corrected) while the anterior electrodes showed inhibition (p < 0.001, cluster-based corrected) in the early stage. However, in the late stage, the posterior electrodes were inhibited (p < 0.001, cluster-based corrected) and the anterior electrodes were activated (p< 0.001, cluster-based corrected). No significant cluster of electrodes was observed during the middle stage. Furthermore, the decoding outcomes for four different choice set sizes were illustrated in Supplemental Figure 1 . The significant time clusters between the two adjacent choice sets (e.g., between 4 and 8) were relatively small; however, as the number of choices that differ between them increases, the significant time clusters become more expansive.