Effects of Stimulus Complexity on the Phonemic Restoration Effect

Area of Science:

• Auditory Perception
• Speech Processing
• Psychoacoustics

Background:

• Phonemic restoration improves speech understanding by replacing silent gaps with masking sounds.
• This phenomenon involves interactions between perceptual continuity and linguistic inference.
• Stimulus complexity, defined by response constraints and linguistic variability, may influence phonemic restoration.

Purpose of the Study:

• To investigate how interruption rate and masking sounds affect phonemic restoration.
• To determine if these effects vary with speech material complexity.
• To examine the relationship between temporal sampling, masking plausibility, and perceptual repair.

Main Methods:

• Young adults with normal hearing performed an interrupted-speech identification task.
• Five speech corpora, ranging from closed-set to open-set, were used.
• Stimuli were interrupted at 2 Hz and 3 Hz, with silent gaps or speech-shaped noise fillers.

Main Results:

• Speech intelligibility was higher for closed-set than open-set materials.
• Replacing silent gaps with noise improved intelligibility across all materials.
• Interruption rate and gap-filler interactions were more pronounced in open-set materials.

Conclusions:

• Phonemic restoration is a reliable process but is influenced by the nature of the speech material.
• Stimulus complexity modulates how temporal processing and masking contribute to speech perception.
• Open-set, high-variability speech materials are particularly sensitive to these complex interactions.