Fig. 1.

Schematic illustration of stimuli for the tasks of perceptual timing. Horizontal lines depict tones (200 Hz, 100 ms). In each case the reference stimulus is shown above the initial target stimulus. As each run progressed, the target stimulus was adaptively controlled to be increasingly similar to the reference stimulus, dependent on participant performance. (A) Var: sub-second variable-interval discrimination. (B) Pul: detection of regularity (pulse, or beat) within an irregular sequence. (C) Iso: detection of deviation from isochrony. (D) Met: detection of the disruption of a sequence with strong metrical structure.