Parallels in Infants' Attention to Speech Articulation and to Physical Changes in Speech-Unrelated Objects

The mechanisms of how children develop the capacity to make use of speech articulation cues to support interpretation of the speech signal are not exhaustively explored. The purpose of this study is to investigate if there are parallels in infants’ way of attending to speech articulation and their perception of physical changes in speech-unrelated objects. The current research questions grew out from an earlier study in which it was found that perception of speech in infants was based on a match between auditory and visual prominence – as opposed to a match between sound and to it corresponding face. Data suggested that speech perception in infancy may function as described by Stevens power law, and two methodological supplements to test the validness of this hypothesis were made in the current study. First, a non-articulatory test condition was added to investigate infants’ perception of speech-unrelated objects. Second, amplitude manipulated stimuli were added to introduce systematic changes in loudness. Results confirmed our hypothesis; the visually prominent articulations were favored, and the same pattern was found in response to nonspeech related objects.