Why IQ may Predict Reading Ability
Why then is IQ widely believed to predict reading ability? Is it because IQ measures potential whereas reading ability is an achievement? It is argued that IQ, as potential, should be manifested or expressed in reading as in other behavior. But, let us note from the example of Wechsler testing that some test items are in fact tests of vocabulary and arithmetic, which are subjects taught in the schools. Even tests of general information are taught in social studies. It is not surprising, then, that we can predict from the IQ score of a child his/her reading, arithmetic, or general learning ability, and that we can reverse the prediction as well.
So IQ may be irrelevant in the diagnosis of reading disability but it may predict reading ability. These predictions can be made mainly because the IQ tests contain questions that are based on school subjects. But is intellectual ability or intelligence in a broad sense, not in the narrow sense of IQ tests, irrelevant for the understanding and prediction of reading disability? It is obviously not so, because we suspect that reading depends on basic intellectual processes.
IQ is Irrelevant but Cognitive Processes are Relevant
What other processes may be critical for word reading besides phono-logical coding? According to some researchers, phonological skills may not tell the whole story because deficient phonological skills are themselves an outcome of difficulties experienced with more fundamental cognitive processes. Indeed, it has been suggested that one cognitive aspect—working memory—is directly related to reading together with phonological processing and syntactic awareness. (Dog bites man and Man bites dog do not differ in syntax but they are different in meaning.)
Working memory is simply like a desktop computer that has the capacity to remember input for short periods of time (RAM). This analogy applies to the limited period of time the child has when working with recently learnt material. For example, if one says to a child, “The blue yellowed the pin” and then asks who was yellowed, the child has to hold the content of the sentence in his/her mind long enough to work out the solution. The child keeps the sentence alive in memory by rehearsing it. This is often done automatically and the child is not even aware of it.
The sentence can also be said to go through an articulation loop. While working memory, and particularly the articulatory (phonological) loop, certainly seems to play a role in reading difficulties, its influence may be too broadly interpreted. For example, not all reading-disabled children exhibit working memory problems. Also, how the development of working memory is specifically connected to reading acquisition is not fully understood or explained. In the light of these shortcomings, we believe that the search for relevant cognitive processes needs simultaneously to include and go beyond working memory.
Our search has led to processes other than phonological ones and answers the question: “Why do some children fail to acquire the necessary phonological coding skills in the first place?” We have proposed that PASS can help explain reading and reading disability.
However, no task requires solely simultaneous or successive processing; it is a matter of emphasis. For example, word reading can involve an interplay of simultaneous and successive processing, letter recognition predominantly involves simultaneous processing, detecting their serial order in a syllable requires successive processing, combining the syllables requires simultaneous processing, and so on. Due to the importance of phonological coding in the early stages of word reading, successive processing is naturally expected to be more important at this level.
Simultaneous processing, in turn, should be more strongly related to reading comprehension than to word decoding. In reading comprehension, simultaneous processing is needed to interrelate meaningful units and integrating them into higher-level units. Planning and attention are necessary at all levels of reading, although common decoding tasks are not likely to be affected by minor differences in these executive processes. However, their importance should rise as a function of task complexity.
We conclude that two types of cognitive processes are necessary for reading acquisition: (a) those that contribute to the development of phonological processing, in particular, and to encoding of print, in general, such as successive and simultaneous processing; and (b) those, such as attention and planning, that allow the successful deployment of phonological and other skills.