Making sense of Stager & Werker (1997)

We had a great mini-conference with Lila Gleitman, Paula Fikkert, Anne Christophe and all of us. Paula Fikkert's talk was probably the one with the most amount of new stuff, since Lila and Anne we are all much familiar with. The best thing about Paula's talk was that it finally made very very clear the most perplexing paper in acquisition, the Stager & Werker (1997), Nature. In this paper, 12 month-olds were able to discriminate /b/ from /d/, but when "taught" than an object is called /bin/, they cannot distinguish /bin/ from /din/. Stager & Werker proposed that, while phonetic detail might be perceived, using it for defining lexical items might be a much harder task. So, by 14 months you finally have enough resorces to succeed. Paula replicated the failure of 12m.o.s to distinguish /bin/ from /din/ in a word-learning situation, the success at distinguishing /b/ from /d/ in a non-word-learning situation, but then showed that the same infants were able to discriminate /bon/ from /don/ in a word-learning situation! How come? Well, they start with the observation that young infants (a) produce words such that the feature on the vowel spreads to all the phonemes (b) coronality is under-specified. So, in the mental lexicon, wherever there is a coronal feature, nothing is entered. Since /i/ is coronal, and since the vowel feature spreads out, nothing is represented, so there is nothing to mismatch.