Head, H.—“Disorders of Symbolic Thinking Due to Local Lesions of the Brain”; British Journal of Psychology, 1921.
Ladd, G., and Woodworth, R. S.—Physiological Psychology; Charles Scribner’s Sons, New York, 1911.
Lashley, K. S.—“Studies of Cerebral Functions in Learning”; Psycho-Biology, 1920.
Monakow, C. von—Die Lokalisation im Grosshirn; Bergmann, Wiesbaden, 1914.
Tilney, F., and Riley, H. A.—The Form and Functions of the Central Nervous System; Hoeber, New York, 1921.
CHAPTER IV
Reading
I. RELATION BETWEEN IQ AND CAPACITY FOR READING
It has been stated that most of the mental functions, which human beings perform, are not elementary, but are capable of analysis into many contributing factors. Reading has been shown by such analysis to be a very complex function, interference in any part of which may result in disability. The causes of failure to learn to read under instruction, therefore, differ from child to child. Huey, who spent years studying the psychology of reading, finally became so imbued with the wonder of the process, that he felt that to know it in all its aspects and ramifications would be to know all psychology.
Correlations between IQ and reading ability, among children of the same age, in both silent and oral reading, are positive and very high. This is especially true of reading for the understanding of sentences. Correlation between general intelligence, as measured by a scale like Stanford-Binet, and reading ability, as measured by a scale like Trabue’s Language Completion, or Thorndike-McCall’s scale for understanding of sentences, reaches as high as .90, and hardly ever in any group falls below .60.
These correlations indicate that general mental maturity is very closely related to learning to read. The very intelligent children are the best readers in by far the majority of cases, while school children who do not learn to read under ordinary instruction, are usually feeble-minded. On the basis of experimentation in this field, Ranschburg suggests that even so mechanical an aspect of reading as ability to call correctly words exposed in a tachistoscope, may serve as a rough means of separating feeble-minded school children from the others. Nevertheless, even with correlation coefficients reaching as high as .90, there may occur occasional cases of very marked discrepancy between general intelligence and ability to read.