Finally, it is also possible that newborn infants segregated the sounds delivered by the 3 instruments, creating separate expectations for each of them. This explanation receives support from our previous results showing that newborn infants segregate tones of widely differing pitches into separate sound streams (6). If this was the case, omission of the bass sound could have resulted in the observed ERP differences without beat being induced. To test this alternative, we presented the test and the control sequences of the neonate experiment to adults, silencing the hi-hat and snare sounds. All stimulation parameters, including the timing of the bass sounds and the probability of omissions (separately for the test and the control sequences) were identical to the neonate experiment.