Variability of the best phase across subjects. The best phase denotes the phase at which a subject has its lowest SRT. (A) The distribution of the best phase at the latency of 100 ms appears relatively uniform. (B). The distribution of the best phase at 250 ms latency is clustered around the phase of 60°, and is significantly non-uniform. (C, D) The SRT s when aligned to the best phase per subject. After this alignment, the SRTs at the latency of 100 ms show no significant variation with phase (black dots and error bars: mean and standard error of the mean of the behavioural experiments; red line: LASSO fit with only the significant terms included). At 250 ms, there is significant variation in the SRT, but less than without alignment.