Words in a sea of sounds: the output of infant statistical learning

One of the first problems confronting infant language learners is word segm entation: discovering the boundaries between words. Prior research suggests that 8-month-old infants can detect the statistical patterns that serve as a cue to word boundaries. However, the representational structure of the o utput of this learning process is unknown. This research assessed the exten t to which statistical learning generates novel word-like units, rather tha n probabilistically-related strings of sounds. Eight-month-old infants were familiarized with a continuous stream of nonsense words with no acoustic c ues to word boundaries. A post-familiarization test compared the infants' r esponses to words versus part-words (sequences spanning a word boundary) em bedded either in simple English contexts familiar to the infants (e.g. "I l ike my tibudo"), or in matched nonsense frames (e.g. "zy fike ny tibudo"). Listening preferences were affected by the context (English versus nonsense ) in which the items from the familiarization phase were embedded during te sting. A second experiment confirmed that infants can discriminate the simp le English contexts and the matched nonsense frames used in Experiment 1. T he third experiment replicated the results of Experiment 1 by contrasting t he English test frames with non-linguistic frames generated from tone seque nces. The results support the hypothesis that statistical learning mechanis ms generate word-like units with some status relative to the native languag e. (C) 2001 Elsevier Science B.V. All rights reserved.