Becker, A. 1 , Schild, U. 2 & Friedrich, C. K. 2
1 University of Hamburg
2 University of Tübingen
Even before birth, infants have the capability to perceive some prosodic information, and language - specific prosodic representations of word stress have been shown in infants as young as 4 months (Friederici et al., 2007). This is well before the first language - specific representation for phonemes emerge at approximately 6 month (vowels, Kuhl et al., 1992). Together these findings suggest independent shaping of pathways related to the processing of prosodic information on the one hand and to the processing of phoneme information on the other. Using auditory word onset priming, we follow the neural processing of word prosody and phonemes from 3 to 9 months after birth. Spoken word onsets (primes) were followed by spoken words (targets). Phoneme and prosody overlap between the primes and the onset syllable of the targets were varied across four conditions: (i) ?phoneme-match, prosody match? (e.g. MA - MAma, Engl. mommy [capital letters indicate stressed syllables); (ii) ?phoneme-match, prosody-mismatch? (e.g., ma- MAma); (iii) ?phoneme-mismatch, prosody-match? (e.g.,SO - MAma); and (iv) ?phoneme-mismatch, prosody-mismatch? (e.g., so-MAma). Event-related potentials (ERPs) were recorded from 3-, 6- and 9-month-olds. We found phoneme priming in all three groups. By contrast, stress priming was seen in the 3-month-olds and in the 9-month-olds, but not in 6-month-olds. That is, language processing appears to focus on phonemes in 6-month-olds by neglecting prosody information. This coincides with the milestone of acquiring language - specific phoneme representations in infancy at 6 month after birth. In 3-month-olds and 9-months-olds phoneme and stress priming did not interact. This reveals independent processing pathways for both types of phonological information. In sum, it appears, that prosody and phoneme processing pathways develop differently and remain independent in the first year of life.