Predictability and adult-child cue weighting differences in speech perception

In this experiment, we tested the hypothesis that adult-child differences in cue weighting are influenced by adult-child differences in knowledge of (a) the relative predictability of wordinitial vs. word-final consonants, and (b) of the relationship between predictability and acoustic salience/distinctiveness. We tested our hypothesis using synthetic speech continua with formant transitions varying from /edi/ to /ebi/, which listeners were encouraged to hear as either “Abe E/Ade E” (VC#V context) or as “A bee/A dee” (V#CV context). We tested the extent to which changes in formant transitions influence /d/ vs. /b/ categorisation. Results show that adults were more influenced by transitions cueing word-initial consonants (less predictable in English) than by transitions cueing word-final consonants (more predictable in English), whereas children showed a more balanced pattern, with marginally more influence of transitions cueing word-final consonants. Results are consistent with the view that adults have learned more about the relative predictability of word-initial vs. word-final consonants and have learned that acoustic cues to the less-predictable initial consonants are more distinctive. They therefore weight these cues more heavily than less-distinctive, more contextually predictable, word-final cues.