Tag Archives: bottom-up processing

Top-down Processing and Dyslexia

While going through bottom-up and top-down processing in this week’s lesson, I found myself relating these different perception approaches to my Dyslexia. These topics gave me an idea of why I may read or perceive words differently than someone without dyslexia. While considering these different approaches, I have realized that my perception of words and sentences deals with top-down processing much more than bottom-up processing. For this blog post, I will provide examples of how I often misread or misperceive words due to top-down processing, and I will explain why bottom-up processing or a combination of the two may be more efficient for reading.

Bottom-up processing deals with sensing raw data from the environment through site, smell, sound, taste, or touch and forming a perception of that data based on the senses. Top-down processing may cause one to perceive that same raw data differently due to making assumptions based on what is expected or considering past experiences while processing the data. Top-down processing is probably not the sole reason for my Dyslexia, but it does help me better understand certain symptoms of my disorder. For example, my family and I recently went on vacation and spent a lot of time driving. While on the road, I noticed that I would often misread signs. If a sign read, “Seasonal Lodging,” my family would see the words and perceive them correctly. I may see the same sign but perceive it as reading, “Logical Reasoning,” due to the somewhat similar ordering of letters and because I am exposed to the term, “logical reasoning” more often than “seasonal lodging,” so that is what I would expect. This is an example of making assumptions based on expectations before the data is fully processed.

Another common mistake that I make deals with seeing numbers among words. If a sign were to read, “80 South,” I may perceive the sign as reading “86 South.” This is because I would not simply make a visual perception based on what I sense through site, as one would with bottom-up processing. Instead, I see the number “80,” so I assume that I am now dealing with numbers. I then see the letter “S” and read it as “6” because of the “S” sound. Instead of making only a visual perception based on my sense of site, I would have combined an auditory perception due to my expectations.

Bottom-up processing may be the more efficient method while reading because it involves visually sensing the letters, decoding the letters to form words, and allowing the words to form complete sentences. This method prevents assumptions and allows for comprehension. Top-down processing may lead one to misread a sentence due to what he or she expects it to say. However, combining the two types of processing may be helpful as well. While top-down processing may cause one to make assumptions, it can also be helpful with understanding the true meaning of a strangely-worded sentence or a sentence with errors. For example, English professors often use the sentence, “Let’s eat, Grandma,” to point out the importance of proper punctuation. Without the comma, the sentence has an entirely different meaning, but top-down processing allows one to use previously acquired knowledge and expectations to realize the intended meaning (Gjessing & Karlsen, 1989, p. 71).

Reading has always been a relatively difficult task for me due to Dyslexia, but this week’s lesson provided me with an understanding of how my perception process may be involved. I have become aware that my reading and comprehension habits deal primarily with the top-down process, which may explain why I add and remove words from sentences and often misread words. With this knowledge, I can attempt to apply the bottom-up process while reading, which may help with the disorder.



Gjessing, H. J., & Karlsen, B. (1989). A longitudinal study of dyslexia: Bergen’s multivariate study of children’s learning disabilities. New York, NY: Spring Science & Business Media.