Figure 6.

Each stimulus pattern contained eight events distributed over eight pulse cycles. Complexity was varied by manipulating the number of events that fell in phase versus anti-phase with the intended pulse. At complexity level 0, all eight events were in-phase, at complexity level 1, one event was anti-phase, at complexity level 2, two events were anti-phase, and so on. Level 4 was the most complex, with four events in-phase and four events anti-phase. One isochronous control (level 0), two level 1 patterns, two level 2 patterns, two level 3 patterns, and four level 4 patterns were used, for a total of 11 rhythms.