Limitations on infants' response to rate-based auditory-visual relations

To study rate-based intersensory matching, infants first were familiarized with different auditory-visual relations and then were tested for detection of auditory-visual equivalence. Across several different experiments, 4-, 6-, and 8-month-old infants first were habituated with (a) a single, tempo-rally concordant auditory-visual compound stimulus, (b) a single, temporally discordant compound stimulus, (c) 2 different, temporally concordant compounds, or (d) a silently moving visual stimulus. A consistent and robust finding was a preference for the visual stimulus that moved at a novel veloc-ity, indicating that the temporal attributes of the visual component dominated responsiveness. Only 1 experiment yielded evidence, albeit limited, of intersensory matching; infants habituated with a silently moving visual stimulus preferred the sound-specified visual stimulus in the presence of the rapid sound but not in the presence of the slow sound. Most objects and events in an infant's everyday world are rep-resented by concurrent attributes in different sensory modal-ities. Many of these attributes specify the same information and, if an infant is to have a unified perceptual experience, he or she must be able to respond to the relational aspects of these attributes. Without a doubt, temporal attributes such as syn-chrony, duration, rate, and rhythmic pattern are the most fre-quent and important sources of auditory-visual relational in-formation (Massaro & Cohen, 1990; Summerfield, 1979). Be-cause of the ubiquity and importance of temporal attributes for intersensory integration, infants ' detection of temporally based intersensory relations has been investigated rather intensively. Investigations of infants ' responsiveness to auditory-visual re