Page:Scientific Monthly, volume 14.djvu/40

 better on this kind of test than on tests of the Binet type, perhaps because it is more subject to the influence of schooling.

K presented no symptoms whatever of psychopathological tendencies, but the Kent-Rosanoff test was given in order to compare his responses with those found by the authors for typical dull subjects. The results showed 14 per cent. of "individual" and 4 per cent. of "doubtful" reactions. Kent and Rosanoff found 6.8 per cent. of individual responses for normal adults, 14.3 per cent. for normal ten-year olds, and 26.8 per cent. for insane adults. Eastman and Rosanoff found 13.2 per cent. for delinquents (presumably averaging much be low normal in intelligence). Accordingly, as far as individual responses are concerned. K's performance resembles that of a dull youth or normal child.

The median frequency of the responses was 22, which is considerably lower than for normal adults. In this case, the low score indicates dull ness rather than mental eccentricity. There were no predicate reactions.

There was only one instance of failure to respond, and seven instances of perseverance. These figures are not greatly different from those found for normal adults.

Average reaction time was 3.1 seconds. ± 1.54. The average for college students is usually between 1.5 and 2.25; for children or men tally inferior adults, about 3. Four responses required more than 10 seconds. K s slow reaction time, as well as the quality of his responses, indicates mental inferiority.

The striking thing in the above table is the rapid deterioration in quality of performance in the successive parts of the test from addition to reasoning. That is, the higher the mental processes involved in a test, the more clearly it brings out K's subnormality. In speed and accuracy of adding he compares favorably with the average high school pupil, while in arithmetical reasoning he is little above fifth-grade ability. Three errors, all as absurd as the following, were made in indicating operations necessary to solve problems: