Six-month-olds' categorization of natural infant-directed utterances.

Abstract

In this study, the authors demonstrated that 6-month-old infants are able to categorize natural, 650 Hz low-pass filtered infant-directed utterances. In Experiment 1, 24 male and 24 female infants heard 7 different tokens from 1 class of utterance (comforting or approving). Then, some infants heard a novel test stimulus from the familiar class of tokens; others heard a test stimulus from the unfamiliar class. Infants categorized these tokens as evidenced by response recovery to tokens from the unfamiliar class but not to novel tokens from the familiar class. Experiment 2 confirmed that the infants were able to discriminate between closely matched tokens from within each category, supporting the conclusion that the results of Experiment 1 indicated categorization. The authors discuss both a mechanism that might explain the development of this ability and the mutual adaptation seen in parent-infant communication.

Categorization of infant‐directed speech: Development from 4 to 6 months

“…We first analyzed the data using the 5% decrement criterion used in both Experiment 1 and Moore et al (1997). This analysis revealed no evidence of categorization.…”

“…The data collected were compared with the results of our previous study (Moore et al, 1997). If the presence of the higher frequencies interferes with infants' processing of unfiltered ID stimuli, then infants should not categorize unfiltered utterances.…”

Intersensory redundancy educates human infants' attention to the prosody of speech

“…Infants also respond with significantly more negative affect while hearing infant-directed phrases conveying prohibition than when hearing infant-directed phrases conveying approval (Fernald, 1993). Similarly, four-month-old infants prefer to listen to infant-directed speech when it specifies approval than when it specifies prohibition (Papousek et al, 1990 (Moore et al, 1997;Spence & Moore, 2003). These studies demonstrate that the prosodic contours characteristic of infant-directed speech over adult-directed speech allow affect and intention to be more accessible to both infants and adults.…”

“…It has been postulated that the exaggerated prosodic patterns characteristic of infant-directed speech have many advantages which aid infants in a multitude of perceptual tasks (Fernald, 1984). Most studies investigating infant-directed speech have been conducted on infants' perception of unimodal auditory speech (e.g., Moore et al, 1997;Spence & Moore, 2003). However, research on audiovisual events indicates that intersensory redundancy in the form of temporal synchrony between auditory and visual stimulation recruits attention and facilitates perceptual learning of the amodal properties (e.g., affect, duration, patterns consisting of tempo, rhythm, and intensity changes) available in infant-directed speech more successfully than when the same information is presented unimodally to only one sensory modality (Bahrick & Lickliter, 2000Bahrick et al, 2007;Castellanos et al, 2004;Flom & Bahrick, 2007).…”

“…Research indicates that across languages adults use infant-directed speech, suggesting that these prosodic modifications function as cross-linguistic universals (Fernald, Taeschner, Dunn, & Papousek, 1989;Grieser & Kuhl, 1988;Papousek, Papousek, & Symmes, 1991). Fernald (1984) has postulated and research has shown that the exaggerated prosodic contours characteristic of infantdirected speech are important for modulating infants' attention and state (Fernald, 1984;Stern, Spieker, Barnett, & Mackain, 1983;Stern, Spieker, & MacKain,1982), conveying affect and intention in speech (Fernald, 1989;Fernald, 1993;Fernald & Kuhl, 1987;Moore, Spence, & Katz, 1997;Papousek, Bornstein, Nuzzo, Papousek, & Symmes, 1990;Spence & Moore, 2003;Trainor, Austin, & Desjardins, 2000;Werker & McLeod, 1989) aiding infants in parsing the speech stream and facilitating learning of sound-meaning relations (Christophe, Gout, Peperkamp, & Morgan, 2003;Fernald & Mazzie, 1991;Gerkin & Aslin, 2005;Hirsh-Pasek et al, 1987;Jusczyk, Hirsch-Pasek, Kemler Nelson, & Kennedy, 1992;Mandel, Kemler Nelson, & Jusczyk, 1996;Morgan, 1996;Nazzi, Kemler Nelson, Jusczyk, & Jusczyk, 2000;Shafer, Shucard, & Jaeger, 1999).…”