Your IQ may determine how well you hear in a crowd

Cognitive Ability and Hearing in Noisy Environments

Researchers studying three groups of people -- individuals with autism, those with fetal alcohol syndrome, and a "neurotypical" control group -- 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.

"The relationship between cognitive ability and speech-perception performance transcended diagnostic categories. That finding was consistent across all three groups," said the study's lead investigator, Bonnie Lau. She is a research assistant professor in otolaryngology-head and neck surgery at the University of Washington School of Medicine and directs lab studies of auditory brain development.

The findings were published in PLOS One.

Intelligence as a Factor in Real-World Listening

Lau noted that the study's small sample -- fewer than 50 participants -- means the results should be replicated with larger groups. Even so, she said the findings indicate that intellectual ability is one of several factors affecting how effectively people listen in complex sound environments, such as busy classrooms or social gatherings.

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.

The "Multitalker" Challenge

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, color, and number, such as "Ready, Eagle, go to green five now."

Participants then selected the colored and numbered box that matched the main speaker's statement as the background voices gradually grew louder.

Afterward, they completed standardized 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.

"We found a highly significant relationship between directly assessed intellectual ability and multitalker speech perception," the researchers reported. "Intellectual ability was significantly correlated with speech perception thresholds in all three groups."

A lot of brain processing contributes to successful listening in complex environments, Lau said.

Hearing Loss vs. Cognitive Processing

"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 study directly addresses a common misconception, Lau added, that any person who has trouble listening is suffering from peripheral hearing loss.

"You don't have to have a hearing loss to have a hard time listening in a restaurant or any other challenging real-world situation," she said.

The researchers suggested that people who are neurodivergent or have lower cognitive ability may benefit from evaluating and modifying their listening environments. In classrooms, for instance, simple adjustments such as placing a student closer to the front or providing hearing-assistive tools could make communication easier.

Lau conducts her work at the UW Virginia Merrill Bloedel Hearing Research Center. Her coauthors represent the UW Autism Center, the Institute for Learning and Brain Sciences, and the departments of bioengineering, epidemiology, pediatrics, radiology, and speech and hearing sciences at the University of Washington, along with the Department of Otolaryngology-Head and Neck Surgery at the University of Michigan, Ann Arbor.