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The Effects of Task Difficulty Predictability and Noise Reduction on Recall Performance and Pupil Dilation Responses
Andreea Micula1,2, Jerker Rönnberg2, Lorenz Fiedler3
1Oticon A/S, Smørum, Denmark.
Ear and Hearing
|April 16, 2021
Summary
Noise reduction improves speech recall and working memory resource allocation in hearing aid users. Pupillometry and a recall test revealed that noise reduction frees up cognitive resources for speech storage, aiding comprehension in noisy environments.
Area of Science:
- Cognitive psychology
- Auditory neuroscience
- Speech processing
Background:
- Traditional speech understanding tests do not capture cognitive processes essential for communication.
- Challenging listening situations demand more working memory for speech processing, reducing storage capacity.
- Understanding how working memory is allocated during speech comprehension in noise is crucial for improving assistive listening devices.
Purpose of the Study:
- To investigate the impact of predictable versus unpredictable task difficulty on working memory resource allocation.
- To examine the effect of noise reduction on working memory resource allocation for speech processing and storage.
- To compare behavioral (Sentence-Final Word Identification and Recall test) and physiological (pupillometry) measures of resource allocation.
Main Methods:
- Twenty-four hearing aid users with moderate to severe hearing loss participated.
- Combined Sentence-Final Word Identification and Recall (SWIR) test with pupillometry.
- Measured pupil dilation and word recall with and without hearing aid noise reduction in four-talker babble noise.
- Manipulated task difficulty predictability by varying sentence list lengths and informing participants beforehand.
Main Results:
- Noise reduction improved recall performance and sentence baseline pupil dilation, especially for longer lists.
- Unpredictable task difficulty led to higher sentence baseline pupil dilation, suggesting altered cognitive strategies or arousal.
- Pupillometry captured cognitive processes not reflected by the SWIR test, indicating complementary measurement capabilities.
Conclusions:
- Noise reduction enhances speech storage capacity by freeing up working memory resources, as evidenced by improved recall and pupil dilation.
- Task difficulty predictability did not significantly affect recall performance, but influenced pupil dilation, suggesting differences in engagement or strategy.
- Combined behavioral and physiological measures provide a comprehensive understanding of cognitive resource allocation in speech comprehension.
