The Effects Of Parental Behaviors And Prosody On The Language And Cognitive Development Of Infants

Abstract

The prosody (i.e., acoustic variations in pitch, intonation, stress patterns, and rate of speech) of infant-directed speech is a salient communicative feature (e.g., Fernald, 1989) that aids in the cognitive and language development of infants (e.g., Kaplan, Bachorowski, Smoski, & Hudenko, 2002; Tamis-LeMonda & Bornstein, 2002). The way parents interact with their children also contributes significantly to infant learning and cognitive development (e.g., Riksen-Walraven, 1978; TamisLeMonda & Bornstein, 2002). Nevertheless, the detailed mechanisms that outline how prosody and parental behaviors (e.g., pointing to an object, touching the infant, smiling) guide infant learning remain less well understood. One approach to better understanding these mechanisms is to examine the caregiver's role during infantcaregiver interactions to determine which prosodic aspects of parental speech, and which accompanying behaviors, most influence infant vocabulary and cognitive development. Longitudinal and intervention studies indicate that level of caregiver responsiveness significantly impacts vocabulary development and rate of learning (Hart & Risley, 1995; Riksen-Walraven, 1978). However, real-time, moment-bymoment proximal interactions should also be examined in order to assess these specific mechanisms at the micro level. Furthermore, given that many of our parental behaviors are shaped during childhood (e.g., Serbin & Karp, 2003), before we can fully understand the mechanisms by which prosody and parental behaviors affect infant development, we must first understand how these mechanisms are acquired. An intergenerational approach to infant learning and cognitive development requires a study of infant-sibling interactions, which can be used as a first step to ascertaining how prosody and parental behaviors can lead to long-term positive developmental outcomes for infants. Therefore, the present dissertation extends the research by: 1) exploring the unique idea that older siblings may already be adopting their caregivers' speech and behavioral characteristics when interacting with infant siblings, 2) examining whether differences in maternal prosody result in differential levels of learning for infants; specifically on infant development of spatial vocabulary, 3) discovering which features of caregiver speech and interaction style are most effective in aiding infant learning and language development, and 4) utilizing the knowledge acquired regarding effective speech and interaction styles to develop an early childhood intervention program. The results of this systematic investigation of parental behavior and prosody add to our knowledge of the relation between parental responsiveness and the subsequent cognitive development of infants. It may also be influential in guiding the way we design early childhood interventions for caregivers and at-risk children.