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Cognitive Compensations for the Visually Impaired

Two summers ago, I volunteered at a special education academic program at the Weston High School in Weston, Massachusetts. As I observed the students work, I was astounded by how behind in learning their disabilities put them compared to the average level their age would normally be associated with. While I was there, I helped a 13-year-old blind girl with her reading comprehension homework. I was asked to dictate a passage to her, and she had to answer one of four questions that she read in brail. As I watched her fingers trace the dots, and dictate to me the correct answer, I was both astounded and intrigued.  I wondered and still wonder, how does the human body adapt and reorganize itself to compensate for deficits, by birth or by injury? More specifically, how can blindness affect one’s cognitive abilities, in particular the various parts of the human memory?

In a recent study (Withagen, A., Kappers, A. L., Vervloed, M. J., Knoors, H., & Verhoeven, L. (2013), researchers conducted one of the first experiments comparing both the working memory and the short-term memory of blind versus sighted children. The researchers chose two, clear research questions to focus on: 1) How do short-term memory and working memory abilities of blind versus sighted children differ 2) To what extent do the short-term memory and working memory abilities relate within the two groups of children? The researchers hypothesized that blind children would have short-term memories and working memories superior to those of the sighted children because of the brain’s adaptation to a visual impairment.

Conceptually, Short-term memory is a passive storage system with a small capacity and a short-duration. Working memory, which refers to a system that stores and rehearses information used to carry out cognitive tasks, contains the central executive, which regulates the cognitive processes, the phonological loop, which stores and rehearses verbal information, the visuo-spatial sketchpad, which stores and rehearses visual information, and the episodic buffer, which connects all the information together. Although the two systems are closely related, it is important to know their distinction from one another when testing the two systems because they are not the same!

For testing STM, both the blind and sighted children performed the Digit Span Forward Test, in which the children had to repeat an increasing number of digits in order, the 15 Word Test For Children, in which the participants had to recall fifteen unrelated words read aloud, and the Learning Names task, in which the participants had to remember the names that various objects were paired with.

In order to test the children’s’ working memory, the researchers made sure to provide more complex tasks that would contain both the memory and processing elements of the working memory. They hoped that these tasks would distinguish this study from previous studies, where working memory wasn’t differentiated from short-term memory. In the Listening Span Task, the children had to listen to sentences out loud, repeat the last words, and then determine whether the sentences were true or false. In the Working Memory Digit Span Backward Task, the participants had to listen to digits and be able to repeat them backwards.

The results of the study confirmed the researchers’ hypothesis that blind children have superior working memories and short-term memories to sighted children. How does this superiority come to be? The results confirm previous theories that the brain reorganizes itself to account for the absence of vision. Because blind people can’t use visual stimuli for recognition and identification, they have to use alternative methods for navigating the world. Therefore, they must develop different strategies to make up for the absence of vision. As a result, they are using their memory more often than sighted people because they have a larger dependency on memory in everyday life. On a more general level, I would imagine that people with various deficits have to compensate in similar ways to blind people have to. I would be interested to know what type of memory compensations people are deaf have to make.

 Withagen, A., Kappers, A. L., Vervloed, M. J., Knoors, H., & Verhoeven, L. (2013). Short term memory and working memory in blind versus sighted children. Research In Developmental Disabilities34(7), 2161-2172. doi:10.1016/j.ridd.2013.03.028


  1. October 7th, 2014 at 17:42 | #1

    This article was very interesting to me because of the focus on children. In choosing children as the subject group, the researchers have opened up a lot of questions about the brain’s re-organization based on the absence of certain systems. If these children were born blind, it would make sense that they would learn how to operate without relying on their visual system. However, what happens if adults lose their sight later on? Would the brain reorganize itself or would it be too late in life to forge these new neuronal connections? How would long-term memory come into play for these adults?

  2. December 6th, 2015 at 15:57 | #2

    I found this article very interesting as I grew up in Weston, the town that the author refers to, and can relate to the experience. It has been known that when an area of the brain is injured or damaged, still new nerve pulses can occur and connections made that may even completely regenerate the affected area. Neuroplasticity acts for this behavior and is reflected in the brain’s neurons ability to be constantly forming new connections. Many sources have attributed this as an increase in other brain areas, potentially compensating for the lost area (Bates, 2012).

    Another study monitored the blood flow with fMRI scanner, which visually showed the increase in brain activity. Deaf adults had increased activity to touch and visual stimuli (Karns, 2012). If the study had examined deaf individuals compared to blind, would there be similar results?

    In the article discussed on the blog, the study was conducted with children. If the study had examined adults rather than children, would there have been different results in terms of memory? The found information of increase activity to touch and visual stimuli may be connected with a potential increase in short term and working memory for deaf adults, similar to the increase in memory for blind children. It would also be interesting if the study was broaden to include not just completely deaf or blind individuals. A study that examines tone deaf, auditory processing disorder, and color-blind individuals would be very interesting to see if alternative pathways are increased including short term and working memory.

    Bates, Mary. “Super Powers for the Blind and Deaf.” Scientific American. N.p., 2012. Web. 06 Dec. 2015.

    Karns. “Altered Cross-Modal Processing in the Primary Auditory Cortex of Congenitally Deaf Adults: A Visual-Somatosensory FMRI Study with a Double-Flash Illusion.” The Journal of NeuroscienceSociety for Neuroscience, 2012. Web. 06 Dec. 2015.

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