Development of perception and perceptual learning for multi-timescale filtered speech

Area of Science:

• Auditory Neuroscience
• Developmental Psychology
• Speech Perception

Background:

• Auditory signal processing, crucial for speech comprehension, shows gradual development.
• The brain's hemispheres process different speech frequencies: right for slow (0-4 Hz), left for fast (22-40 Hz).

Purpose of the Study:

• To investigate the developmental trajectory of filtered speech perception and learning in adolescents (8-19 years).
• To determine the effects of diotic and dichotic presentation of low and high frequency speech bands on perception and learning.
• To examine hemisphere-specific processing benefits for filtered speech.

Main Methods:

• Participants (8-19 years) perceived and learned filtered speech (0-4 Hz and 22-40 Hz) presented diotically and dichotically.
• Dichotic presentation was tested for both preferred and non-preferred hemisphere laterality.
• Performance was assessed across age groups and presentation conditions.

Main Results:

• Filtered speech perception and learning improved with age, continuing into adolescence.
• Dichotic presentation of both low and high frequency bands yielded the best performance across all ages.
• No significant benefit was observed for dichotic presentation to the preferred hemisphere, suggesting integration across both ears.
• Learning was maximized with dichotic presentation, especially for individuals with initially lower performance.

Conclusions:

• Auditory processing of temporally filtered speech develops throughout adolescence.
• Integrating slow and fast speech components via dichotic presentation enhances perception and learning, independent of hemisphere specialization.
• Findings do not support cochlear implant strategies based on differential filtering to each ear but highlight the potential for learning in poorer performers.