Articulatory gestures are individually selected in production

Area of Science:

• Speech production
• Articulatory phonetics
• Cognitive neuroscience

Background:

• Speech planning models often assume sequential selection of speech segments (consonants, vowels).
• Associated articulatory features or gestures are thought to be automatically selected post-segmental selection.
• An alternative hypothesis suggests gestures themselves undergo selection, allowing for independent co-occurrence failures.

Purpose of the Study:

• To investigate whether articulatory gestures are selected independently or as a consequence of segmental selection.
• To test the prediction that gestures affiliated with the same segment may fail to co-occur.

Main Methods:

• A stop-signal task was employed, requiring participants to produce syllables (/pa/ or /ka/-initial).
• Participants halted speech production upon receiving a stop-signal within 300 ms of a go-signal.
• Articulatory kinematics were measured using a speech magnetometer.

Main Results:

• Vowel-affiliated gestures (glottal adduction, tongue body lowering, bilabial opening) did not consistently co-occur when speech production was halted.
• Observed failures in gesture co-occurrence challenge the automatic consequence model.

Conclusions:

• Articulatory gestures are selected individually, not solely as a byproduct of segmental selection.
• Findings support a model where gestures are subject to their own selection process during speech planning.