Psychobiological Responses Reveal Audiovisual Noise Differentially Challenges Speech Recognition.
Gavin M Bidelman, Bonnie Brown, Kelsey Mankel and 1 others
PMID 31283529WHAT IT FOUND
When listening to sentences, sound noise hurt recognition more than visual static.
As listening got harder, gaze shifted from mouth to eyes; looking at the mouth tracked better recognition.
Key findings
01Noise in the sound channel made sentences harder to recognize than noise over the talker's face, even when the two noise types were matched in overall physical clarity.
02Visual cues still helped speech recognition when the visual channel was degraded, but visual degradation alone did not reduce recognition when the audio channel was clear.
03When auditory noise was present, fixations at the eyes increased, and more fixations on the mouth were associated with better recognition.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The participants were 22 young adults with normal hearing and self-reported normal or corrected vision, so the results may not apply to older adults, people with hearing loss, vision loss, or clinical populations. Vision was not formally screened, so subtle differences in visual acuity could have influenced gaze and recognition. Only one male talker and one female talker were used, so talker-specific effects may not generalize to other voices or faces. The auditory and visual noise were matched by physical signal-to-noise ratio, but not by perceived difficulty, so the larger effect of sound noise may partly reflect unequal task demands. The sample included 15 women and 7 men, which may have contributed to the lack of participant gender effects. The study measured behavior and gaze in a laboratory listening task; it did not test any treatment or clinical outcome. Visual-only sentences produced floor performance, so the study could not test visual noise in the visual-only condition.
Declared interests
The supplied text does not include a funding or conflicts-of-interest declaration. The publication types list NIH extramural research support.
The easy way to misread this
Do not conclude that training people to look at the mouth will improve speech recognition. The study only found an association between more mouth fixations and better scores in young adults with normal hearing, and it did not test any intervention.