ERP correlates of word onset priming in infants and young children

• Word onset priming appears to be a powerful method for investigating early lexico-phonological processes.
• Based on word onsets, infants seem to make phonological predictions about word forms.
• Adult-like word form access seems to develop only after the second year of life.

Using word onset priming with early learned words, we tracked access to phonological representations and predictive phonological processing at 6, 12, 18, and 24 months after birth. Event-Related Potentials (ERPs) were recorded while participants heard German word onsets (primes) followed by disyllabic spoken words (targets). Primes and target onsets were either congruent or incongruent (ma – Mama vs. so – Mama [Engl. ‘mommy’]). For an adult control group, ERP differences were found for the N100 complex, which has been related to abstract auditory analysis; and for the P350 deflection, which has been related to lexical access. A combined analysis of all infants and young children revealed an immature instance of an N100 effect, suggesting adult-like abstract speech sound processing. A central negativity effect, which had formerly been obtained when adults or older children were engaged in a lexical decision task, suggests that adult-like predictive phonological processing is available early in infancy. However, the absence of a P350-like effect in the infant data suggests that adult-like access to phonological forms is not established in the first two years of life. Taken together, ERPs recorded in word onset priming proved useful in investigating early phonological processing without an explicit behavioral measure.