Neural-Behavioral Relation in Phonetic Discrimination Modulated by Language Background

Area of Science:

• Neuroscience
• Linguistics
• Psychology

Background:

• Listeners exhibit superior discrimination of native phonetic contrasts compared to non-native ones.
• Neuroimaging studies using mismatch negativity/response (MMN/R) show neural differences in processing native versus non-native speech sounds.
• Direct correlations between behavioral discrimination and MMN/R are infrequently reported.

Purpose of the Study:

• To investigate the relationship between behavioral phonetic discrimination and neural responses (MMR) in native English and Spanish speakers.
• To examine how a non-native speech contrast (Spanish VOT) is processed by native speakers of English and Spanish.
• To explore individual differences in the neural mechanisms of speech sound discrimination.

Main Methods:

• A behavioral discrimination task measuring sensitivity (d') to a voice-onset-time (VOT) contrast.
• Magnetoencephalography (MEG) recording to measure the mismatch response (MMR) to the same VOT contrast.
• Comparison of behavioral and neural data between 15 native English speakers and 15 native Spanish speakers.

Main Results:

• Native English speakers demonstrated lower behavioral sensitivity (d') and a more expansive MMR to the non-native contrast compared to native Spanish speakers.
• Native Spanish speakers showed significantly better behavioral discrimination of the VOT contrast.
• A significant correlation between behavioral sensitivity and MMR was found only in the native Spanish speaker group.

Conclusions:

• Behavioral and neural responses to speech contrasts differ between native and non-native language groups.
• The relationship between behavioral discrimination and neural processing (MMR) may be language-specific.
• Individual differences in neural mechanisms underlie behavioral performance in speech sound discrimination across different language backgrounds.