An event-related potential (ERP) study of duration changes in speech and non-speech sounds

PROCESSING of the duration changes in speech and non-speech sounds was investigated using event-related potentials (ERPs). In Experiment 1, participants were presented with sequences of repetitive stimuli (tones or vowels) interspersed with changes (shortening or lengthening) in duration. For tones, lengthened stimuli elicited a larger mismatch negativity (MMN) component compared to shortened, whereas for vowels, shortened elicited a larger MMN than lengthened. Experiment 2 was conducted to determine if the effects in Experiment 1 were the result of simple differences in spectral complexity. The data confirmed the interpretation in Experiment 1 that the degree to which stimuli are 'speech-like' determines how duration changes are processed. These data suggest that duration changes are processed differentially for speech and non-speech stimuli. NeuroReport 10:3301-3305 (C) 1999 Lippincott Williams & Wilkins.