190 SECTIONAL ADDRESSES 
make provision for the education of their children at age five, and most 
children begin to go to school at or about that age, any serious backward- 
ness in this direction probably indicates some intellectual deficiency. 
If we assume that the average child can read sufficiently well at age nine, 
then this test, so far as the reading difficulty goes, was suitable for about 
go per cent. of the age-group that was examined. Another difficulty 
arises from the fact that one set of questions must be given to suit all levels 
of mental development from mental age nine upwards. A few of out- 
standing ability may not have taken the test, others may not have been 
examined fully enough to show all their ability, and none of those so 
markedly defective as to be certified for institutional care were examined : 
the findings regarding those at the extreme ends of the intellectual scale 
are, therefore, somewhat uncertain. Still, the general significance of the 
inquiry is quite clear. 
The average agreed with previous estimates, but the dispersion proved 
to be greater than had previously been supposed—in other words, there 
were more who were dull and more who were bright: about half the 
population examined had mental ratios between 89 and 111 (instead of 
_ between gi and gg, as was previously supposed), and it was estimated 
that in the whole population between 14 and 3 per cent. fell below the 
70 line, that is, below the line which is commonly supposed to mark the 
boundary between mental defect and normality. The average of the boys 
was the same as that of the girls, but their dispersion was greater, that is, 
there were amongst them more who were very bright and more who were 
dull. This distribution has important implications, of which I shall con- 
sider only one, and that very briefly—namely, its bearing on the rate at 
which boys and girls leave school after completing the work of the primary 
school. ° 
In Scotland about 44 per cent. of the children of age twelve embark 
on a secondary school course ; of these 70 per cent. begin the second year 
work, 43 per cent. the third, 22 per cent. the fourth, 15 per cent. the fifth, 
and g per cent. the sixth. Of those who pass to the ‘ Advanced Divisions ’ 
only 14 per cent. enter on a third-year course. ‘These educational casual- 
ties are due to many causes ; some fall out for economic reasons, others 
find—or think they find—a better preparation for the serious business of 
life elsewhere (and these include some of the brightest), but probably 
most drop out because school seems to be a testing-ground rather than a 
training-ground, a means of picking out the brightest. ‘This suggestion 
finds some support in the fact that it is the duller pupils who drop out 
first, the very pupils who are most in need of training. It has been 
estimated that a boy or girl must have an intelligence-ratio of 115 or over to 
profit without undue strain from a secondary school education ; this may 
be an over-estimate, but there can be little doubt that the average secondary 
school curriculum is unsuitable for the boys and girls whose ratios fall 
below the mean, that is, for half the school population. The bulk of the 
population are of average or nearly average intelligence—about 68 per 
cent. have mental ratios between 84 and 116—and it seems reasonable to 
ask whether a national system of post-primary education should not give 
first consideration to these rather than to the 16 per cent. at the upper end 
