People who struggle to follow conversations in noisy places may be limited more by cognitive ability than by hearing. New research finds that intelligence plays a key role in how well people process speech in noisy environments.
The study compared neurotypical and neurodivergent individuals and found that cognitive ability predicted performance across all groups. This challenges the idea that listening struggles are solely due to hearing loss, emphasising the brain’s role in decoding complex soundscapes.
The insight came about from the University of Washington School of Medicine researchers studying three groups of people — individuals with autism, those with fetal alcohol syndrome, and a “neurotypical” control group.
The scientists found that cognitive ability strongly influenced how well participants understood speech in noisy conditions. All participants had normal hearing, yet their performance varied based on their intellectual abilities.
Conducting the study
To test their hypothesis, researchers recruited people with autism and fetal alcohol syndrome, both groups known to experience challenges with listening in noisy settings despite normal hearing. Including these neurodivergent participants also provided a wider range of IQ scores, with some scoring above average, allowing for a more comprehensive comparison than studying neurotypical individuals alone.
The study included 12 participants with autism, 10 with fetal alcohol syndrome, and 27 neurotypical individuals matched by age and biological sex. Ages ranged from 13 to 47 years. Each participant first completed an audiology screening to confirm normal hearing, then took part in a computer-based listening task.
During the task, participants listened to a main speaker’s voice while two other voices spoke simultaneously in the background. The goal was to focus on the main speaker, who was always male, while ignoring the distractions. Each voice delivered a short command that included a call sign, colour, and number, such as “Ready, Eagle, go to green five now.”
Participants then selected the coloured and numbered box that matched the main speaker’s statement as the background voices gradually grew louder.
Afterwards, the subjects completed standardised intelligence tests measuring verbal and nonverbal ability as well as perceptual reasoning. The researchers compared those results with performance on the multitalker listening test. The results showed a clear connection between intelligence and listening skill.
Assessment
According to lead scientist, Bonnie Lau: “The relationship between cognitive ability and speech-perception performance transcended diagnostic categories. That finding was consistent across all three groups.”
She adds: “You have to segregate the streams of speech. You have to figure out and selectively attend to the person that you’re interested in, and part of that is suppressing the competing noise characteristics. Then you have to comprehend from a linguistic standpoint, coding each phoneme, discerning syllables and words. There are semantic and social skills, too — we’re smiling, we’re nodding. All these factors increase the cognitive load of communicating when it is noisy.”
The research appears in the journal PLoS One, titled “The relationship between intellectual ability and auditory multitalker speech perception in neurodivergent individuals.”
