At the Cognitive Hearing Lab, we’re interested in how people understand speech in challenging listening environments. To communicate effectively with each other, people frequently need to understand what someone’s saying when background noise is present. Even listening to a friend speak at a busy restaurant can be difficult when other people are having loud conversations at nearby tables.
To explore this process, we use a combination of methods, including psychophysics, neuroimaging (EEG, MEG, and fMRI), pupillometry, computational modelling, and questionnaire development.
You can click on the following links or scroll down to read a summary of the topics that we research:
- How do cognitive factors improve speech perception in noisy places?
- How does hearing loss affect speech perception in noisy places?
- Why do some people without detectable hearing loss report substantial difficulty listening in noisy settings?
- How can we improve listening in noisy places?
For a full list of the lab’s publications, see Emma Homes’ Google Scholar or NCBI page.
How do cognitive factors improve speech perception in noisy places?
One theme of our research is to investigate how people focus their attention on a sound of interest—for example, a friend speaking in a noisy place. Our research examines how cognitive factors influence perception, effort, and the ways in which the brain processes sounds in these environments.
One factor that improves speech intelligibility in noisy environments is being familiar with a person’s voice, which relies on long-term memory representations. We’ve found that knowing the person who’s speaking provides a large benefit to speech intelligibility—improving the accuracy of reporting sentences by 10–25% when it’s spoken by a close friend or partner compared to when it’s spoken by a stranger. As well as naturally familiar voices (e.g., friends and spouses), we’ve also studied voices that we’ve trained in the lab to become familiar. This work demonstrates that people are able to better understand speech spoken by new people after they’ve been trained to recognise their voice. Our ongoing work investigates the processes by which voices become familiar, and the conditions under which people benefit from familiar voices.
We’ve also shown that many people benefit from knowing characteristics of an upcoming talker (e.g., the location or identity of the talker) before the talker starts speaking—they’re better at understanding what the talker has said when they have longer to prepare (up to 2 seconds). Even before a talker starts speaking, many people engage brain activity to prepare for characteristics of an upcoming talker (e.g., the location or identity of the talker). Our ongoing work compares how various cognitive factors affect speech perception, and the brain regions that are recruited for speech perception.
Relevant publications:
- Holmes, E., Kitterick, P. T., Summerfield, A. Q. (2016). EEG activity evoked in preparation for multi-talker listening by adults and children. Hearing Research, 336, 83–100. doi:10.1016/j.heares.2016.04.007
- Holmes, E., Kitterick, P. T. & Summerfield, A. Q. (2018). Cueing listeners to attend to a target talker progressively improves word report as the duration of the cue-target interval lengthens to 2,000 ms. Attention, Perception, & Psychophysics, 80(6), 1520-1538. doi:10.3758/s13414-018-1531-x
- Holmes, E., Parr, T., Griffiths, T. D., & Friston, K. J. (2021). Active inference, selective attention, and the cocktail party problem. Neuroscience and Biobehavioral Reviews, 131, 1288-1304. doi:10.1016/j.neubiorev.2021.09.038
- Holmes, E., Purcell, D. W., Carlyon, R. P. et al. (2018). Attentional modulation of envelope-following responses at lower (93–109 Hz) but not higher (217–233 Hz) modulation rates. JARO, 19, 83–97. doi:10.1007/s10162-017-0641-9
- Holmes, E., Domingo, Y., & Johnsrude, I. S. (2018). Familiar voices are more intelligible, even if they are not recognized as familiar. Psychological Science, 29(10), 1575–1583. doi:10.1177/0956797618779083
- Domingo, Y., Holmes, E., & Johnsrude, I. S. (2020). The benefit to speech intelligibility of hearing a familiar voice. Journal of Experimental Psychology: Applied, 26(2), 236–247.
- Holmes, E., To, G., & Johnsrude, I. S. (2021). How long does it take for a voice to become familiar? Speech intelligibility and voice recognition are differentially sensitive to voice training. Psychological Science, 32(6), 903–915. doi:10.1177/0956797621991137
How does hearing loss affect speech perception in noisy places?
People with hearing loss often find listening in noisy environments difficult and effortful, even when they use hearing aids. Another theme of our research is to investigate how people with hearing loss focus their attention on sounds in noisy places.
We’ve found that people with hearing loss prepare their attention for an upcoming talker less than people without hearing loss do. We’ve observed this both in children with early-onset hearing loss and in older adults who have age-related hearing loss. Thus, this difference in preparing attention is likely to be one reason why people with hearing loss often find it difficult to listen in noisy places.
Nevertheless, people with hearing loss may be able to use other forms of cognition to help them listen in noisy places. For example, we’ve shown that when people with hearing loss know the topic of conversation, they’re able to understand speech better and with less effort. Our ongoing work examines how hearing loss affects the strategies that people use to understand speech, and how it influences the brain regions that are recruited for speech perception.
We’re also interested in how hearing challenges affect people’s lives more broadly. For example, difficulty understanding speech in noisy places can cause people with hearing loss to withdraw from social situations. Our ongoing work seeks examine how hearing loss affects participation in social activities that involve various acoustic challenges.
Relevant publications:
- Holmes, E., Folkeard, P., Johnsrude, I. S., & Scollie, S. (2018). Semantic context reduces sentence-by-sentence listening effort for listeners with hearing impairment. International Journal of Audiology, 57(7), 483–492. doi:10.1080/14992027.2018.1432901
- Holmes, E., Kitterick, P. T. & Summerfield, A. Q. (2017). Peripheral hearing loss reduces the ability of children to direct selective attention during multi-talker listening. Hearing Research, 350, 160–172. doi:10.1016/j.heares.2017.05.005
- Caso, A., Griffiths, T.D. & Holmes, E. (2024). Spatial selective auditory attention is preserved in older age but is degraded by peripheral hearing loss. Scientific Reports, 14, 26243. doi:10.1038/s41598-024-77102-5
We’re also interested in why some people find it very difficult to understand speech in noisy environments, despite having no detectable hearing loss. Researchers and clinicians don’t fully understand the cause(s) of this difficulty or how it can be treated. Our research has shown that some of this difficulty may arise from problems grouping sounds, which we measured using a non-linguistic figure-ground task. This task appears to tap into grouping processes in early auditory cortex that are similar to those involved in understanding speech in noisy environments. We found that even young people with no detectable hearing loss vary substantially in how well they can understand speech in noisy environments—and their grouping ability predicted their ability to understand speech when background noise was present. We found a neural correlate of this effect in auditory cortex. In another study, we found that the ability to hold sounds in mind over several seconds (working memory for frequency) helped to predict the ability to understand speech. These findings imply that cognitive processes in auditory cortex might help to explain why some people without detectable hearing loss have substantial difficulty listening in noisy settings.
Relevant publications:
- Holmes, E., & Griffiths, T. D. (2019). ‘Normal’ hearing thresholds and fundamental auditory grouping processes predict difficulties with speech-in-noise perception. Scientific Reports, 9, 16771. doi:10.1038/s41598-019-53353-5
- Holmes, E., Zeidman, P., Friston, K. J., & Griffiths, T. D. (2021). Difficulties with speech-in-noise perception related to fundamental grouping processes in auditory cortex. Cerebral Cortex, 31(3), 1582–1596. doi:10.1093/cercor/bhaa311
- Holmes, E., Utoomprurkporn, N., Hoskote, C., Warren, J. D., Bamiou, D., & Griffiths, T. D. (2021). Simultaneous auditory agnosia: Systematic description of a new type of auditory segregation deficit following a right hemisphere lesion. Cortex, 135, 92–107. https://doi.org/10.1016/j.cortex.2020.10.023
- Lad, M., Chu, A., Holmes, E., & Griffiths, T. D. (2020). Speech-in-noise detection is related to auditory working memory precision for frequency. Scientific Reports, 10, 13997. doi:10.1038/s41598-020-70952-9
How can we improve listening in noisy places?
As well as identifying the processes underlying difficulty listening in noisy places (for people with and without hearing loss), we’re also interested in developing interventions that might help to improve speech perception for various people, and make listening less tiring and effortful. For example, we’re interested in applying our work on voice familiarity to help improve people’s perception of trained voices. We’re also interested in modelling the processes that contribute to speech perception, with the goal of inspiring future hearing-aids that incorporate knowledge of human cognition. We’re open to collaborations in this area.
Cognitive Hearing Lab 