The Abilities of Adolescent and Adult High-Grade Male Defectives

Abstract

During the first half of 1049 a battery of cognitive and personality tests was given to a sample of 104 adolescent and adult high-grade male defectives resident in Darenth Park, Dartford. The testing was carried out by N. O'Connor and the writer, in collaboration with Dr. J. M. Crawford, Deputy Superintendent of Darenth Park. The following report presents a summary of the cognitive and motor test findings, and discusses some of their implications.

Assessment of the Feebleminded

“…Whereas on the other hand, the verbal bias of this test may overestimate the gi of a grammar-school boy. Tizard et al (1950) used five different tests on 104 adult ' high-grade' male patients, namely the block Design, the Progressive Matrices 1938, the Stanford-Binet Vocabulary, the Porteus Mazes, and Cattell's Non-Verbal Intelligence test Form I.B. Their unusual finding was that in spite of the mean I.Q.…”

Shifting boundaries between the normal and the pathological: the case of mild intellectual disability

“…First, there are problems with the calibration of different versions of I.Q. tests over time such that it is not at all clear that a test result of 70 gained today is equivalent to a test result of 70 gained early in the twentieth century (Tizard, O'Connor, Crawford 1950;Flynn 1984Flynn , 1987Flynn , 1998Scullin 2006) . Second, individuals are only seen as being candidates for diagnosis if in addition to having a low I.Q.…”

“…Although the theoretical arguments for detaining mildly intellectually disabled people had collapsed, 'high-grade' residents were still detained, with many remaining in in some numbers in institutions for intellectually disabled people (Tizard, O'Connor and Crawford, 1950).…”

“…Shifting has occurred for two main reasons. First, there are problems with the calibration of different versions of IQ tests over time, such that it is not at all clear that a test result of 70 gained today is equivalent to a test result of 70 gained early in the twentieth century (Flynn, 1984(Flynn, , 1987(Flynn, , 1998Scullin, 2006;Tizard, O'Connor and Crawford, 1950). Second, individuals are only seen as being candidates for diagnosis if, in addition to having a low IQ, their behaviour is judged unacceptable, and what counts as unacceptable has shifted over time.…”

Mind the gap: MIND, the mental hygiene movement and the trapdoor in measurements of intellect

“…For instance, they published studies showing that the IQ of patients classified as ‘feebleminded’ had been under-estimated by earlier and less sophisticated tests (e.g. Tizard 1950; Tizard and O’Connor 1952). Tizard and O’Connor judged the average IQ of these people at over 70%.…”