Researchers examined how skill in language influences cognitive processing, which means how the brain handles thinking tasks like planning and remembering. Language helps not just with talking but also with organizing thoughts and controlling actions. This is true for spoken words or sign language. Many deaf children from hearing families miss early language exposure during the critical period, a key time for learning language that affects later skills. This delay can weaken executive functions, the mental skills for planning, focusing, and switching tasks, but the issue comes from language gaps, not deafness itself.
The study used data from 24 deaf adults and 20 hearing ones, matched for age and other traits. Deaf participants varied in language background; some learned British Sign Language first, others English. Skills were tested with grammar tasks in both languages, taking the best score for a fair measure.
The researchers have described the methods and results of this study in a paper published in Cerebral Cortex.
Key findings from brain scans
Participants did thinking tasks in an MRI scanner, which uses magnets to image the brain. Functional MRI, or fMRI, tracks blood flow to show active brain areas. Tasks tested working memory, holding information briefly, and planning, like solving puzzles. Brain networks studied included the task-positive network, active during hard work in frontal and parietal areas, and the task-negative network, quieter during focus but active at rest.
Results showed deaf and hearing groups performed similarly, but in deaf adults, higher language skill linked to stronger activity and functional connectivity—better teamwork among brain parts—in the working memory network. This effect was not seen in planning or easier tasks. Language in any form supports thinking, and other factors like family interactions or education may help too. The work highlights how early experiences shape brain function, even if not obvious in behavior.
Future research will explore these links across ages to understand lifelong effects of language and senses on cognition.