Listening in noisy spaces can be challenging but new research from Macquarie University Hearing shows human brains are constantly learning to help people tune in and a bit of background echo might help.
The researchers discovered how the human brain learns to ‘listen to the room’, and how this can help people understand speech in noisy, echo-filled spaces.
The research, which looks at how people can unconsciously adjust to different kinds of background noise, is the first study to show how humans adapt to echoey environments to improve their speech understanding.
Senior author of the paper, Distinguished Professor David McAlpine, Academic Director of Macquarie University Hearing, said findings would feed into the design of hearing and listening devices, such as hearing aids and headphones.
“Most hearing technology tries to eliminate all background noise and echo,” he said in The Lighthouse, Macquarie University’s news showcase. “But if some reverb actually helps people hear better, then we may be throwing out something that the brain finds useful.”
Funded by the Australian Research Council, the study was published online in eLife on 2 September 2025.
It builds on earlier work that showed animals’ brains quickly adapt to changes in sound levels.
The study placed volunteers with normal hearing in the university’s anechoic chamber which is free of reverberation.
Using recordings from real spaces, including an underground car park, a lecture theatre, and an open-plan office, the researchers simulated different levels of reverberation, or echo.
Participants listened to short speech commands in conjunction with background noise and reported what they heard.
Prof McAlpine said participants improved at understanding speech over time, even in difficult spaces. Over the course of the 45-minute test, people got better at recognising speech because their brains were learning the ‘sound of the room’.
“What was surprising was that they learned best in the ‘Goldilocks’ zone, which are spaces with ‘just the right’ amount of echo – about 400 milliseconds of reverberation, which is typical of many modern spaces like lecture theatres,” he said.
“Environments with too much echo, like marble-filled lobbies or underground car parks, both made learning to listen much harder as did, counterintuitively, rooms with no echo at all.
“This sweet spot or ‘Goldilocks’ zone, seems to match the average reverberation of spaces we spend most of our time in.
“It’s possible we’ve designed our buildings to fit our brains — or that our brains have adapted to these buildings.”
Echoes enable adjustment
Dr Heivet Hernández-Pérez, first author of the study, said hearing speech in a slightly echoey environment gave the brain time to adjust and recognise patterns.
Dr Hernández-Pérez is a Research Fellow in the Macquarie University Hearing Research Centre and the Macquarie University Department of Linguistics.
“It’s not about remembering the room consciously. It’s about your brain learning the structure of the environment and using that to make sense of speech, even without you realising it,” she told The Lighthouse. “Our ears hear, but our brains listen.
“They’re constantly adapting through feedback loops, learning and changing on the fly.”
As part of the study, the team used magnetic brain stimulation to briefly disrupt an area of the brain involved in learning.
When they did, participants’ ability to adapt to different sound environments dropped significantly.
“This shows us there are specific brain circuits responsible for this kind of learning,” Dr Hernández-Pérez said.
“Understanding how they work could help us develop better, more inclusive sound environments, whether we’re talking about public spaces or personalised hearing technology.
“It’s important to recognise that listening is an immersive experience, shaped by our environments, our brains and how the two interact.
“We’re not just hearing sounds. We’re hearing the world through those sounds.”
The team is now designing new studies to explore how neurodivergent people and people with hearing loss experience reverberation, and whether their ‘Goldilocks’ zones are different from those of neurotypical listeners.
Macquarie University team propose new theory on how humans hear; neural circuitry
