Foundational Tuning: How Infants ’ Attention to Speech Predicts Language Development

Orienting biases for speech may provide a foundation for language development. Although human infants show a bias for listening to speech from birth, the relation of a speech bias to later language development has not been established. Here, we examine whether infants ’ attention to speech directly predicts expressive vocabulary. Infants listened to speech or non-speech in a pref-erential listening procedure. Results show that infants ’ attention to speech at 12 months signifi-cantly predicted expressive vocabulary at 18 months, while indices of general development did not. No predictive relationships were found for infants ’ attention to non-speech, or overall atten-tion to sounds, suggesting that the relationship between speech and expressive vocabulary was not a function of infants ’ general attentiveness. Potentially ancient evolutionary perceptual capacities such as biases for conspecific vocalizations may provide a foundation for proficiency in formal systems such language, much like the approximate number sense may provide a foundation for formal mathematics