Age-Specific Preferences for Infant-Directed Affective Intent

Abstract

This study examined the developmental course of infants' attentional preferences for 3 types of infant-directed affective intent, which have been shown to be commonly used at particular ages in the first year of life. Specifically, Kitamura and Burnham (2003) found mothers' tone of voice in infant-directed speech is most comforting between birth and 3 months, most approving at 6 months, and most directive at 9 months. Thus, the aim of this study was to assess whether there is a relation between the type of affective intent used by mothers at each age point, and infants' affective intent preferences. Each infant group, 3-, 6-, and 9-month-olds, was played the 3 types of affective intent alternating across a single test session. When analyzed across age, the interactions revealed the predicted developmental trajectory; that is, infant preferences transformed between 3 and 6 months from comforting to approving, and between 6 and 9 months, from approving to directive. However, when analyzed separately by age, it was shown that 3-month-olds preferred comforting to other types; 6-month-olds preferred approving to directive, but listened equally to approving and comforting; and 9-month-olds showed no preference for any type of affective intent. Because it was possible that 9-month-olds were more focused on phonetic and phonotactic information, a new group of 9-month-olds was tested with intonation-only versions of the 3 affective intent types. Under these conditions, they were found to prefer directive to comforting, but not directive to approving types. The results of this study have implications for what infants pay attention to in their social and linguistic environment over the course of the first year.

Notes

¹It should be noted that the original affective intent type was labeled affection to encompass the categories of approval and reward, but the use of the label approving in this study is more appropriate as it aligns the findings with categories that are more typically found in the ID speech literature (Fernald, 1993; Katz et al., 1996; Papousek et al., 1991; Stern et al., 1982).

²The female speaker, who had experience as a mother and in the field of ID speech research, memorized the words in each of the utterances, and spoke spontaneously in the presence of a life-size baby doll.

³In pilot testing, adults rated slowed exemplars as more comforting than the original exemplars.