Table 1.

Transition probability diagram

First tone Neutral (p = 0.33)	Second tone
	Expected (p = 0.75)	Unexpected (p = 0.25)
Stimulus 1 (N = 200)	Repetition (stimulus 1) (N = 150)	Omission (no stimulus) (N = 50)
Stimulus 2 (N = 200)	Omission (no stimulus) (N = 150)	Repetition (stimulus 2) (N = 50)
Stimulus 3 (N = 200)	Alternation (stimulus 2) (N = 150)	Alternation (stimulus 1) (N = 50)

The pitch of the first tone could be one of three stimuli with equal probability. The second tone followed the first tone with a probability of 0.75 (expected trials) or 0.25 (unexpected trials), and was of the same pitch (repetition trials), of a different pitch (alternation trials), or omitted (omission trials).