Reading is such a basic, yet vital, component of our lives. Without the ability to read, we would be unable to comprehend a street sign telling us to stop, a crucial headline in the daily news, or an email telling us that the class we hate the most has been cancelled. Unfortunately, there are people whose ability to read is either impaired or entirely nonexistent. Much research has been done on the reading process and how it is affected by brain impairment; at Rice University, Dr. Simon Fischer-Baum and his team are currently studying the reading deficiencies of stroke patients. Before examining a special case of someone with a reading deficit, an understanding of the fundamentals of reading is necessary.
As English speakers, we might assume the reading process starts with the letters themselves. After all, children are commonly taught to identify each individual letter in the word and its sound. Next, the individual strings the individual sounds together to pronounce the word. Finally, once the words have been identified and pronounced, the person refers to his or her database of words and finds the meaning of the word being read.
While letters are the smallest tangible unit of the words being read, they actually depend on an even more basic concept: Abstract Letter Identities (ALIs). ALIs are representations of letters that allow a person to distinguish between different cases of the same letter, identify letters regardless of font, and know what sound the letter makes. It would appear that the ability to read is entirely contingent on one’s knowledge of these letter identities. However, certain scenarios indicate that this is not entirely true, raising questions about how much influence ALIs have on reading ability.
Dr. Fischer-Baum’s lab is currently exploring one such scenario involving a patient named C. H. This patient suffered from a stroke a few years ago and, as a result, has a severely impaired capacity for reading. Dr. Fischer-Baum and David Kajander, a member of the research staff, have given C. H. tasks in which he reads words directly from a list, identifies words being spelled to him, and spells words that are spoken to him. However, his case is especially interesting because he processes individual letters with difficulty (for example, matching lowercase letters with their uppercase counterparts), yet he can still read to a limited extent. This presents strong evidence against the importance of ALIs in reading because it contradicts the notion that we must have some knowledge of ALIs to have any reading ability at all. It has become apparent that C. H. is using a method of reading that is not based on ALIs.
There are several methods of reading that C. H. might be using. He could be memorizing the shapes of words he encounters and mapping those shapes onto the stimuli presented to him, a process called reading by contour. If this were the case, then he should have a limited ability to read capital letters since they are all the same height and width. C. H. could also utilize partial ALI information and making an educated guess about the rest of the word. If that were true, then he should be very good at reading uncommon words since there are fewer words that share that letter sequence.
In order to pursue this hypothesis, Dr. Fischer-Baum’s lab gave C. H. a task derived from a paper by Dr. David Howard. Published in 1987, the paper describes a patient, T. M., who shows reading deficiencies that are strikingly similar to those of C. H.1 A new series of reading tasks and lexical decision tasks from this paper required C. H. to determine whether or not a stimulus is a real word. For the reading tasks, a total of 100 stimuli, 80 words, and 20 non-words were used, all varying in length, frequency, and ease of conjuring a mental image of the stimulus. For the lexical decision tasks, 240 stimuli, 120 words, and 120 non-words were used, all varying in frequency, ease of forming a mental picture, and neighborhood density (the number of words that can be created by changing one letter in the original word). Additionally, each of the word lists was presented to C. H. in each of the following formats: vertical, lowercase, alternating case, all caps, and plus signs in between the letters. These criteria were used to create the word lists, which were then presented to C. H. in order to determine which factors were influencing his reading.
After the tasks were completed and the data was collected, C. H.’s results were organized by presentation style and stimuli characteristics. For reading tasks, he scored best overall on stimuli in the lowercase presentation style (30% correct) and worst overall on stimuli in the plus sign presentation style (9% correct). Second worst was his performance on the vertical presentation style (21% correct). For the lexical decision tasks, we saw that C. H. did best on stimuli in the all capital letter presentation style (79.58% correct) and worst on stimuli in the vertical presentation style (64.17% correct), although his second worst performance came in the plus sign presentation style (65% correct). Across both the reading and lexical decision tasks, he scored higher on stimuli that were more frequent, shorter in length, and easier to visualize. In the lexical decision tasks, he scored higher on low-neighborhood density items than high-neighborhood density items.
These results lead us to several crucial conclusions. First, C. H. clearly has a problem with reading words that contain interrupters, as evidenced by his poor performance with reading the plus sign words. Second, C. H. is not using contour information to read; if he were, then his worst performances should have come on the all caps reading tasks, since capital letters do not have any specific contour. Evidence suggests he is indeed using a partial guessing strategy to read because he performed better on low-neighborhood density words than on high-neighborhood density words. These conclusions are significant because they suggest further tests for C. H. More importantly, these conclusions could be especially helpful for people suffering similar reading deficits. For example, presenting information using short, common, and non-abstract words could increase the number of words these people can successfully read, increasing the chance of them interpreting the information correctly. Dr. Fischer-Baum’s lab plans to perform further tasks with C. H. in order to assess his capacity for reading in context.
References
- Howard, D. Reading Without Letters; The Cognitive Neuropsychology of Language; Lawrence Erlbaum; 1987; pp 27-58.
