Recognizing spoken language is a rapid process, and recent research sheds light on how individuals navigate this challenge to understand words. The study highlights three key strategies employed by people of all ages, including those with cochlear implants, in word recognition.
Researchers from the University of Iowa have explored how individuals identify words.
A recent investigation involving cochlear implant users has uncovered three primary methods that individuals, regardless of their hearing abilities, use to understand spoken words—an essential component for grasping spoken language. The specific method utilized varies from person to person: some may take a brief moment before recognizing a word, while others might ponder between two or more options before choosing the word they heard.
Upon hearing a word, the brain quickly evaluates countless possible options and eliminates most of them in under a second. For example, when someone hears “Hawkeyes,” their brain might briefly consider words such as “hot dogs,” “hawk,” and “hockey” before arriving at the correct one.
Even though the brain reacts swiftly and differences in word-recognition techniques can be subtle, the results of this study are significant. They could offer new insights for hearing specialists to detect word-recognition issues in young children or older adults who often experience hearing loss, enabling better management of these conditions.
“Our findings indicate that there isn’t a single method for word recognition; people have their unique ways of tackling this challenge,” explains Bob McMurray, F. Wendell Miller Professor in the Department of Psychological and Brain Sciences and lead author of the study. “It’s fascinating to realize that language usage is not uniform among individuals.”
McMurray has dedicated three decades to researching how both children and older adults recognize words when spoken. His previous findings indicated subtle variances in recognition strategies across different ages, which made categorizing these differences challenging. Consequently, McMurray and his research team focused on cochlear implant users—individuals with profound hearing loss who utilize devices that bypass natural auditory pathways, using electrodes to convey sound.
“It’s essentially replacing millions of hair cells and thousands of frequencies with just 22 electrodes, which can make sounds less distinct. Nevertheless, this system works because the brain has the ability to adapt,” states McMurray.
The research involved 101 participants from the Iowa Cochlear Implant Clinical Research Center at the University of Iowa Health Care Medical Center. Participants listened to words spoken through loudspeakers and subsequently chose the matching image from a set of four on a computer screen. Their responses and eye movements were tracked using technology that allowed researchers to observe how and when participants arrived at their word choice, all within a fraction of a second.
The findings indicated that cochlear implant users, even with their unique auditory experience, followed similar fundamental processes for word selection as those with normal hearing.
The research team identified three dimensions of word recognition:
- Wait and See
- Sustained Activation
- Slow Activation
Most cochlear implant participants demonstrated some degree of the Wait and See strategy, whereby they paused for up to a quarter of a second after hearing a word before making a firm decision about it.
Previous studies in McMurray’s lab have indicated that children with early hearing loss also exhibit Wait and See tendencies, but such patterns had not been observed more broadly.
“This may allow them to narrow down their choices and simplify the decision-making process,” McMurray suggests.
The research also revealed that some cochlear implant users leaned towards Sustained Activation, where they contemplate several word options before finalizing their choice, or they tended to Slow Activation, indicating a lag in recognizing words. Notably, each listener appears to utilize a combination of these strategies, with varying levels of each.
These dimensions correspond with the recognition patterns found in individuals without hearing impairments, across different age groups, as demonstrated in earlier studies by McMurray’s group.
“Having identified these dimensions within the cochlear implant cohort, we can now investigate their applicability to people without hearing loss, and we observe that the same dimensions apply across the board,” McMurray explains. “What we observe in how cochlear implant users recognize words is reflective of processes at play in many individuals.”
The researchers now hope to leverage their findings to develop strategies that can assist those facing extreme challenges in word recognition. Approximately 15% of adults in the U.S. experience hearing loss, which can lead to cognitive decline, decreased social engagement, and increased isolation.
“We want to create more refined methods than merely asking if someone is having difficulty hearing,” McMurray notes.
The study titled “Cochlear implant users reveal the underlying dimensions of real-time word recognition” was published online on August 29 in the journal Nature Communications.
Other contributors from Iowa include Francis Smith, Marissa Huffman, Kristin Rooff, John Muegge, Charlotte Jeppsen, Ethan Kutlu, and Sarah Colby.
The research was funded by the National Institutes of Health and the U.S. National Science Foundation, which have supported the Iowa Cochlear Implant Clinical Research Center for 30 years.
