Newborns' brains Detect Foreign Rhythm in Native-language Speech

Area of Science:

• Developmental Psychology
• Linguistics
• Neuroscience

Background:

• Infants demonstrate prenatal sensitivity to native language prosody, including rhythm.
• Previous research shows newborns process speech directionality and intonation, but rhythm processing is less understood.
• Traditional theories posit newborns only detect broad, categorical rhythm differences.

Purpose of the Study:

• To investigate how newborns process temporal rhythm patterns in naturalistic native-language speech.
• To determine if newborns can discriminate between native and foreign rhythmic patterns in their language.
• To explore the hemispheric lateralization of speech rhythm processing in newborns.

Main Methods:

• Hemodynamic activity was recorded in Czech-learning newborns (N=44).
• Newborns listened to Czech utterances with either native Czech rhythm or foreign-accented rhythm.
• Foreign-accented rhythm featured prolonged foot-initial syllables, contrasting with native rhythm's lack of prominent stress cues.

Main Results:

• Newborns exhibited larger hemodynamic responses to native-language speech with foreign rhythm compared to native rhythm.
• This heightened response to foreign rhythm was most pronounced in the right hemisphere.
• Findings indicate right-lateralized processing of speech rhythm differences.

Conclusions:

• Newborns can discriminate between native and foreign rhythmic patterns using gradient temporal cues alone.
• This discrimination occurs even when the native language does not fit traditional rhythm classifications.
• Early language discrimination is more nuanced than previously thought, relying on subtle acoustic temporal information.