View report page

There is not a great difference between the groups except that in group B, where instability
was more marked than illiteracy, there appears perhaps a wider range of variation among the
children than in group A. On the whole it is evident that instability is at least as important a
factor as dullness.
To obtain some indication of how far intelligence as measured by tests is related to practical
capacity the defective mothers were placed in two groups—those of lower grade (mental age
below 9), and those of more intelligence (mental age 9 or over). A visit was paid to the homes,
and many organisations to whom the defectives might be known were consulted. In this way
it was possible to make a fair estimate of the comparative success or failure of their lives within
the community, and as a result the two groups were allocated as efficient or inefficient housekeepers
as follows:—
Mothers.
Efficient
housekeepers.
Inefficient
housekeepers.
Total.
Mental age—
A. Under 9 12 69 81
B. 9 and over 43 37 80
Some of the satisfactory homes in group A may be ascribed to the fact, sometimes established,
that, the wife being obviously incapable, the husband (not defective) has taken her place ; and
some of the bad homes in group B are attributable to the fact that the defective, although of better
intelligence, showed marked instability. The table illustrates a fact well-known to social workers,
that defectives, especially those of low grade, will, if left to themselves, bring down the level of
any environment.
A genealogical tree, fig. 3, shows the occurrence of many defectives in one family. The
mental status of the early ancestry is not known, but Mr. and Mrs. L. are known to have
both been dull, and Mr. V.2, who married the eldest daughter of Mr. and Mrs. L., is known to
have been unstable and to have paralysis, almost certainly due to specific disease. All were
slum dwellers for a long time. It will be noted that many members of the family are mentally
defective, and some of those not themselves defective, gave birth to defective children. There is
not, however, any regular sequence of mental defective—normal—dull-—mentally defective.
This family has gained some notoriety and is thought by some to be typical. In our series of
families it was, however, unparalleled.
To ascertain the frequency of pockets of defectives, 294 families were analysed and divided
into three groups:—
Group A—Those with three other known defectives in the immediate family ;
Group B—Those with one or two other defectives ;
Group C—Those in which the defective was unique.
The immediate family includes parents and children of the defective, brothers and sisters,
nephews and nieces. The numbers in each of the three groups were 12, 65 and 197, respectively.
The circumstances giving rise to the worse pockets are evidently of much importance. We
had not the opportunity of investigating the question in detail, but our data, incomplete as they
are, do suggest some likely factors. The mentality of the grandparents on one side only was
known.
In group A, 16.6 per cent. of the parents of the defectives were normal, and 66 per cent, of
the families were slum dwellers; in group B, 38 per cent. of the parents were normal, and the
majority had undesirable homes; in group C, 62 per cent. of the parents were normal, while only
6 per cent. were slum dwellers.