N400 Evidence That the Early Stages of Lexical Access Ignore Knowledge About Phonological Alternations.

The participants were native Mandarin speakers without a reported clinical disorder, so the study does not show how people with speech, language, or hearing difficulties process these tones. Some participants were excluded because their EEG data had substantial artifacts, so the analysed sample was smaller than the recruited sample. The monosyllable task did not place tones in the normal context where the alternation occurs, so participants may have had no reason to expect a variant. In the disyllable task, the critical syllable was never followed by the tone that would license the alternation, so the context was still not fully natural. The brain measure may not isolate the N400 cleanly, and the authors state that other overlapping components could affect the result. The task asked participants to compare a heard sound with a seen character, which may involve conscious matching rather than automatic prediction.

The paper reports funding from Hong Kong Polytechnic University.

Do not conclude that phonological knowledge is irrelevant to language comprehension. This study tested only early brain responses when a heard tone mismatched an expected tone, and the authors say such knowledge may matter at later stages.