The following study examined how young infants learn to detect the amodal properties available in prosodic speech (e.g., affect, duration, patterns consisting of tempo, rhythm, and intensity changes) in contexts where intersensory redundancy is not available. It is proposed that the detection of amodal properties in redundant audiovisual stimulation can "educate" selective attention (Gibson, 1979), to those same properties in subsequent nonredundant stimulation (Lickliter, Bahrick, & Markham, 2006). If so, then infants pre-exposed to redundant audiovisual as compared with nonredundant unimodal auditory speech should discriminate amodal properties of prosodic speech during nonredundant unimodal auditory habituation and testing sessions. Results confirmed predictions and support the hypothesis that, during early development, sensitivity to the amodal properties available in prosodic speech emerges in the context of intersensory redundancy and is later extended to contexts where intersensory redundancy is not available.
