Infants’ short-term memory for consonant–vowel syllables

Abstract

This research examined whether the auditory short-term memory (STM) capacity for speech sounds differs from that for nonlinguistic sounds in 11-month-old infants. Infants were presented with streams composed of repeating sequences of either 2 or 4 syllables, akin to prior work by Ross-Sheehy and Newman (2015) using nonlinguistic musical instruments. These syllable sequences either stayed the same for every repetition (constant) or changed by one syllable each time it repeated (varying). Using the head-turn preference procedure, we measured infant listening time to each type of stream (constant vs varying and 2 vs 4 syllables). Longer listening to the varying stream was taken as evidence for STM because this required remembering all syllables in the sequence. We found that infants listened longer to the varying streams for 2-syllable sequences but not for 4-syllable sequences. This capacity limitation is comparable to that found previously for nonlinguistic instrument tones, suggesting that young infants have similar STM limitations for speech and nonspeech stimuli.