In the novelty oddball task (Friedman et al., 1993; Fabiani and Friedman, 1995), ERPs were measured to infrequent target tones, frequent standard tones, and to nontarget novel sounds (e.g., animal sounds, environment sounds, musical instruments). Each subject first received 4 blocks of 50 trials in a standard auditory oddball task. Each block contained a series of two tones in a random order (ISI = 1,000 ms), with one tone (500 or 350 Hz) being the frequent stimulus (P = 0.88) and the other being the infrequent target stimulus (P = 0.12). Subjects responded with a button press to the target tones. The session continued with 8 additional blocks of the novelty oddball task, in which novel sounds (P = 0.12) were intermixed with the infrequent target tones (P = 0.12) and the frequent tones (P = 0.76). Subjects were not informed that the novel sounds would be presented, and if they asked questions about their presence, they were reminded to respond only to the target tones. Target tones were 300 ms in duration and the 48 unique novel sounds ranged
