w examples of experimental work given in Professor McDougall's
book will suffice to show the trend of these results.

Tests of intelligence were carried out on recruits for the American
Army, white and coloured, and they shewed marked superiority of the
white race.

A special test was carried out in Oxford by Mr. H.B. English, who
compared the capacity of boys in a school attended by children of the
intellectual classes with that of boys in a very good primary school,
whose fathers were shop-keepers, skilled artisans, etc., coming from
homes which were good, with no sort of privation. The result showed
marked superiority of the sons of intellectual parents. Mr. English
concludes that the children of the professional classes, between 12
and 14 years of age, exhibit very marked intelligence, and he is
convinced that the hereditary factor plays an altogether predominant
part.

In another experiment, Miss Arlitt, of Bryn Mawr College, tested 342
children from primary schools in one district, who were divided into
four groups:--

Group 1. Professional.
Group 2. Semi-professional and higher business.
Group 3. Skilled labour.
Group 4. Semi-and unskilled labour.

Marked differences between the groups were shewn. The intellectual
capacity was represented by figures as follows:--

Group 1 125
Group 2 118
Group 3 107
Group 4 92

A further research of 548 children, grouped according to the
occupation of their father, gave its results in terms of the
percentage of children in each group who scored a mark higher than the
median for the whole 548. They are as follows:--

Professional group 85%
Executive group 68%
Artisan group 41%
Labour group 39%

In the "Journal of Educational Psychology," Vol. IX, 1916, Mr. A.W.
Kornhauser gives evidence from the examination of 1,000 children drawn
from five schools in Pittsburgh.

Schools A and B were attended by children of unskilled manual workers.

Schools C and D by children of skilled artisans and small shopkeepers.

School E by children of parents in very comfortable circumstances.

The results are tabulated as--

Retarded, _i.e._, below average.
Normal, _i.e._, average.
Advanced, _i.e._, above average.

| Retarded. | Normal. | Advanced.
A } Manual workers {| 45.2 | 47.1 | 7.7