Individual variability as a window on production-perception interactions in speech motor control

Area of Science:

• Speech motor control
• Auditory perception
• Speech production

Background:

• Understanding the interplay between speech production and perception is crucial for speech motor control.
• Theoretical frameworks suggest speech production targets may be specified in auditory terms.
• This study investigates the link between auditory acuity and speech production precision.

Purpose of the Study:

• To test if individuals with better auditory acuity exhibit more precise speech production targets.
• To determine if enhanced auditory discrimination correlates with decreased within-phoneme variability and increased between-phoneme distance.
• To explore the relationship between auditory feedback and speech production precision over time.

Main Methods:

• A counterbalanced study design involving perception and production tasks.
• Auditory acuity was measured using an adaptive speech discrimination task.
• Speech production variability was assessed via a pseudo-word reading task, quantifying within-phoneme variability and between-phoneme contrasts.

Main Results:

• Significant individual differences in both speech production and perception abilities were observed.
• Individuals with better auditory discrimination showed more distinctive vowel production targets.
• This distinctiveness was characterized by reduced within-phoneme variability and greater between-phoneme distances.
• The observed association was independent of phoneme density in vowel space.

Conclusions:

• Better auditory acuity is associated with more precise speech production targets.
• This finding supports the hypothesis that speech production targets are specified in auditory terms.
• Auditory feedback mechanisms likely play a role in refining speech production precision over time.