The development of infants' preference for motherese

Generally, infants prefer infant-directed (ID) to adult-directed (AD) speech. Mostly, researchers have used unfamiliar female voices in these studies. We investigated preferences for maternal ID speech in 1- and 4-month-olds. Using a procedure in which infants controlled access to voices by fixating a visual display, infants listened to recordings of natural female ID and AD speech. In Experiment 1, 1-month-olds heard recordings of maternal ID and AD speech, but these infants showed no preference for maternal ID speech. In Experiment 2, 1-month-olds heard the same ID and AD speech tapes but were not familiar with the speakers. Contrary to Experiment 1, these infants preferred ID speech. In Experiment 3, 4-month-olds heard recordings of maternal ID and AD speech and showed a significant preference for ID speech. Collectively, these results suggest that infant attention to ID speech depends on both speaker-general and speaker-specific characteristics, with interesting developmental changes occuring during early infancy.