INFANTS DISCRIMINATION OF BIMODAL EVENTS ON THE BASIS OF RHYTHM AND TEMPO

A habituation procedure was used to examine 7-month-old infants' discrimination of changes in the rhythm (Expt 1) or the tempo (Expt 2) of an auditory-visual event. Events consisted of videos of a hammer striking a surface displaying a characteristic rhythm and tempo along with the synchronized impact sounds. In Expt 1, 32 infants were habituated to one rhythm presented at a constant tempo followed by test trials of a novel rhythm presented at the familiar tempo. Across subjects, four different stimulus rhythms were presented at each of four different constant tempos. Infants demonstrated significant visual recovery to a novel rhythm at all stimulus tempos. In Expr 2, 32 infants were habituated to events displaying one rhythm and tempo followed by test trials presenting a novel tempo and the familiar rhythm. Infants showed a significant visual recovery to a novel tempo, which was apparent across four different underlying rhythm contexts. More robust discrimination was observed for more extreme tempo contrasts. These data suggest that 7-month-old infants are sensitive to the invariant rhythm and tempo of bimodal events.