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48
The 14 super-normal children were mostly noted by the teachers as likely to be fit for
scholarships or central schools when old enough. One older girl had been found fit for a trade
scholarship.
It was noted that the education level for the children of defectives was lower than their level
of intelligence. In 162 children over 7 in elementary schools the reading age was above the
mental age in 35, equal to the mental age in 28, below the mental age in 99.
In 30 cases the inferiority was over 2 years or more. The calculation age was above the mental
age in 5, equal to the mental age in 19, and was below it in 138, in 38 cases inferiority being more
than two years. This inferiority as regards reading was probably associated with the poor
cultural level of the families. The reading level is better in residential schools, but not the
calculation.
The poor cultural level of a child's family and associates was reflected in the result of the
vocabulary test. Comparing results of this test with that of the serial intelligence tests the relations
were—above mental age, 17 ; equal to mental age, 20 ; below mental age, 50.
Performance tests, which are least influenced by culture of the family, gave—above mental
age, 48 ; equal to mental age, 40 ; below mental age, 18.
The distribution of intelligence in these children compared with those in an ordinary population
is shown in fig. 2. Curve A from data in Terman's "Measurement of Intelligence,"
shows the distribution as regards intelligence in 1,000 unselected children in an area of good
social status. Curve B shows the distribution in the offspring of defectives. It will be noted
that the contours of the two curves bear a general resemblance, but in the case of children with
a mentally defective parent (B) the maximum point (intelligence quotient 86 to 95) is
removed 10 degrees below the level (96 to 105) in A, and this relation holds good for the whole
of the curve. Similar curves for the distribution of intelligence in average and poor areas
are not available, but curve C, based on the findings of Dr. Porteus, given in " Intelligence and
Social Valuation," by Berry and Porteus, illustrates the intelligence distribution for a poor average
population (in Australia), though this fails to discriminate at the ends of the scale and does not
mark off the mentally defective or highly super-normal.
Professor Burt has stated that the average intelligence quotient in a " poor " school at age
7 is 87, compared with 129 for a school in a " superior " area. Comparing the diagrams it would
appear that the offspring of the defectives have a distribution of intelligence much like that of
children in a very poor area, and range from super-normal to imbecile, there being more subnormal
than super-normal, but not a suddenly marked out mass of mental defectives.