Infant distractibility from social events mediates the relation between maternal responsiveness and infant language outcomes.

Research demonstrates that contingent and appropriate maternal responsiveness to infant requests and bids for attention leads to better language outcomes. Research also indicates that infants who are less distracted by irrelevant competing stimulation and attend efficiently to audiovisual social events (e.g., faces and voices) show better language outcomes. However, few studies have assessed relations between maternal responsiveness, infant attention to faces and voices, and distractibility, and how together these factors lead to early language outcomes. A newly developed audiovisual protocol, the Multisensory Attention Assessment Protocol (MAAP; Bahrick et al., 2018), allows researchers to examine individual differences in attention to faces and voices and distractibility, and to assess relations with other variables. At 12 months, infants (n = 79) in an ongoing longitudinal study participated in the MAAP to assess intersensory matching of synchronous faces and voices and attention to an irrelevant competing visual distractor event. They also were observed in a brief play interaction to assess infant bids for attention and maternal responsiveness (accept, redirect, or ignore). At 18 months, receptive and expressive language were assessed using the Mullen Scales of Early Learning. Several noteworthy findings emerged: 1) mothers were generally responsive, accepting 74% and redirecting 14% of infant bids, 2) infants who had a greater number of their bids redirected by mothers, and who had better intersensory matching of synchronous faces and voices, showed less attention to the distractor, and 3) infants who showed less attention to the distractor had better receptive language. Findings demonstrate that maternal redirecting of infant attention by mothers who are generally responsive may promote better infant attentional control (lower distractibility) which in turn predicts better receptive language in toddlers.

Intersensory redundancy promotes infant detection of prosody in infant-directed speech.

Prosody, or the intonation contours of speech, conveys emotion and intention to the listener and provides infants with an early basis for detecting meaning in speech. Infant-directed speech (IDS) is characterized by exaggerated prosody, slower tempo, and elongated pauses, all amodal properties detectable across the face and voice. Although speech is an audiovisual event, it has been studied primarily as a unimodal auditory stream without the synchronized dynamic face of the speaker. According to the intersensory redundancy hypothesis, redundancy across the senses facilitates perceptual learning of amodal information, including prosody. We predicted that young infants who are still learning to discriminate and categorize prosodic information would detect prosodic changes better in the presence of intersensory redundancy (i.e., synchronous audiovisual speech) than in its absence (i.e., unimodal auditory or asynchronous audiovisual speech). To test this hypothesis, 72 4-month-old infants were habituated to recordings of women reciting passages in IDS with prosody conveying either approval or prohibition and then were tested with recordings of a novel passage with either a change or no change in prosody. Infants who received bimodal synchronous stimulation exhibited significant visual recovery to the novel passage with a change in prosody, but not to a novel passage with no change in prosody. Infants in the unimodal auditory and bimodal asynchronous conditions did not exhibit visual recovery in either condition. Results support the hypothesis that intersensory redundancy facilitates detection and abstraction of invariant prosody across changes in linguistic content and likely serves as an early foundation for the detection of meaning in fluent speech.