The Results of Repeated Mental Reëxamination of 639 Feeble-minded over a period of Ten Years

Abstract

In 1911 a ten-year program was begun by reëxamining all the inmates of the Minnesota School for Feeble-minded, at regular intervals of two years. Cases over 20 years, epileptics, and others in whom some special trait interfered with getting a reliable mental age, were omitted.A summary may be briefly expressed as follows: (1) The mental ages of the feeble-minded increase with age at a rate proportionate to the degree of mental deficiency. (2) On the whole the mental age ceases to increase between the ages of fifteen and eighteen, the idiot grade ceasing development about three years earlier than the borderline grade. (3) The lower grades lose more frequently in mental age than the higher grades. (4) The frequency in loss in mental age increases with age, independently of grade. (5) The intelligence quotient decreases with age, and more for the higher than for the lower grades. (6) The intelligence quotient of cases above the average will increase with age instead of decrease, for the same reason that it will decrease for cases below average. From Psych Bulletin 19:03:00248. (PsycINFO Database Record (c) 2016 APA, all rights reserved)