Infant attention to auditory discrepancy.

Groups of 7 1/2-month-old infants heard 1 of 8 episodes consisting of no, slight, moderate, or a large discrepancy between a habituated standard and a transformed auditory stimulus. The patterns of cardiac deceleration, regarded as an index of attention supported the hypothesis that attentiveness is an inverted-U function of the degree of discrepancy between stimulus event and schema.