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Report of the Medical Officer (Education).
151
a more complete examination at which the child has ample opportunity to become accustomed to the
examiner demands an expenditure of time which would allow not only of a definite opinion, but of some
contributions to the psychology of education.
Certain psychological investigations were made in the schools by pupils of Dr. Spearman, with the
permission of the Education Committee. The most important was presented as a thesis at the University
of London by A. R. Abelson. It was on the Measurement of Mental Ability of backward Children.
The work has extended over three years. Individual examinations were carried out on 131 children
in 8 schools, 18 different tests being used. Only one test was used on any occasion. The work was
always done in a separate room, quite free from any disturbance, and plenty of time was allowed for
the observer and observed to get on friendly terms. The children examined were those who presented
least evidence of defects, and who whilst they cannot make sufficient progress in the ordinary schools,
yet advance considerably in the special school. Abelson designated them merely backward, but adds
that these "backward children are of all mentally defectives the most interesting, since they are the
most amenable to treatment." The main aim of the enquiry appeared to be the principles upon which
practical tests of efficiency must be based.
At the start 14 groups of tests were tried. The following nine were continued through the enquiry,
namely:—
Tapping test—to measure simple motor action.
Crossing out rings test—to measure rapidity of motor co-ordination.
Crossing out sets of dots—to measure one form of quickness of perception.
Geometric figure test. Power of placing a pointer within certain geometric figures.
Immediate memory for sentences, names and commissions.
Discrmination of length.
Interpretation of pictures.
Only the last three of these tests, memory for commissions, discrimination of length and the
interpretation of pictures have been commonly used by the medical officers in the estimation of mental
deficiency.
The whole of this work may, however, be regarded as an independent enquiry, as the methods
of testing have been somewhat different, being more to measure the value of the tests, as well as to
determine mental response.
The teachers' estimates of the practical intelligence of the children, and their attainments in
arithmetic and reading were compared with the results of the tests. The boys and girls were separately
graded in order according to their success in each test and according to the teacher's estimate of intelligence,
reading, and arithmetic. The correlation co-efficient was then determined for each pair of groups.
Each test was repeated and its reliability tested by these methods of correlation. The degree of reliability
of the finished results were found to be high. There was an even and appreciable correlation
between the results of the tests in the case of the girls, the average being .32. In the case of the boys
smaller and more fluctuating values were obtained, with an average of .26. This point was noted early
in the investigation, so that after only four schools had been visited girls alone were examined. It
thus seems far harder to estimate a boy's intelligence by a few tests than that of a girl. The distribution
of mental attainments being apparently more even among girls. Neither reading nor arithmetic
correlate highly with other performances. They are no better, indeed, if anything, worse, than an
average single test. Nor do they go together, an observation made by both teachers and doctors long
ago, although not quantitatively estimated. The teachers' estimates of intelligence correlated mostly
with arithmetical capacity, memory for commissions and sentences, and reading ability, the commissions
memory was closest wTith girls, and reading with boys. This, Abelson points out, probably gives a clue
to the working of the teachers' minds rather than to the mental capacities of the children. His
conclusions are that:—
It is time to abandon too exclusive reliance on casual and intangible general impressions, especially
when these have to be derived from a single brief interview.
Certain conceptions, such as that individuals may be classified into distinct types according
to their mental processes, are becoming obsolete.
Methods of diagnosis should be checked by numerical estimates and correlation co-efficients.
The results obtained give no support to the faculty theory in psychology, so that a report
by an examiner that he had tested memory, observation, judgment, reasoning, muscular co-ordination
and so forth, would arouse no confidence in the procedure, on the part of the author. Of the tests
themselves, all tests alike proved untrustworthy when used alone, the cardinal principle must be to
pool several independent tests. When the tests are properly constructed and suitably graded any
one of them is just about as effective as another. Moreover, the apparent intellectuality of a test
may be very misleading. An unquestionably defective child may perform a test almost incredibly well
while perfectly normal children may meet with surprising failure. More fundamental is the principle
that the tests should be thorough enough to give results of some constancy. It is best for children on
the border line between normal and deficiency and at least over eight years old always to use the
same tests and make allowance for age. This is the usual method of the medical officers.
He thinks half an hour should be allowed for the examination and re-examination of each child,
but his method would seem to require an even longer time.
He concludes that the general nature of mental deficiency is a "general lowering of that class
of performances which is characterised by the need of clear consciousness. . . . The reason for applying
a large number of tests is not to gauge a number of different factors in ability, but merely to obtain
multiple evidence as to this one factor, the general level." This conclusion, at present popular, must be