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IntelligenceAverage Intelligence (i Q 90 To 110)
Alternative Test 1: Repeating Six Digits
List Of Tests
The Relation Of The I Q To The Quality Of The Child's School Work
Other Fallacies In The Estimation Of Intelligence
Superior Adult 1: Vocabulary (seventy-five Definitions 13500 Words)
Intelligence Tests Of Superior Children
The Intelligence Of Retarded Children Usually Overestimated
Vocabulary; Twenty Definitions 3600 Words
Average Adult Alternative Test 2: Comprehension Of Physical Relations
Naming Familiar Objects
Comparison Of Weights
Reliability Of Repeated Tests
Repeating Five Digits
Border-line Cases (usually Between 70 And 80 I Q)
The Necessity Of Standards
The Distribution Of Intelligence
Alternative Test 3: Construction Puzzle A (healy And Fernald)
Feeble-mindedness (rarely Above 75 I Q)
There are innumerable grades of mental deficiency ranging from somewhat below
average intelligence to profound idiocy. In the literal sense every individual
below the average is more or less mentally weak or feeble. Only a relatively small
proportion of these, however, are technically known as feeble-minded. It
is therefore necessary to set forth the criterion as to what constitutes
feeble-mindedness in the commonly accepted sense of that word.
The definition in most general use is the one framed by the Royal
College of Physicians and Surgeons of London, and adopted by the English
Royal Commission on Mental Deficiency. It is substantially as follows:--
_A feeble-minded person is one who is incapable, because of mental
defect existing from birth or from an early age, (a) of competing on
equal terms with his normal fellows; or (b) of managing himself or his
affairs with ordinary prudence._
Two things are to be noted in regard to this definition: In the first
place, it is stated in terms of social and industrial efficiency. Such
efficiency, however, depends not merely on the degree of intelligence,
but also on emotional, moral, physical, and social traits as well. This
explains why some individuals with I Q somewhat below 75 can hardly be
classed as feeble-minded in the ordinary sense of the term, while others
with I Q a little above 75 could hardly be classified in any other
In the second place, the criterion set up by the definition is not very
definite because of the vague meaning of the expression "ordinary
prudence." Even the expression "competing on equal terms" cannot be
taken literally, else it would include also those who are merely dull.
It is the second part of the definition that more nearly expresses the
popular criterion, for as long as an individual manages his affairs in
such a way as to be self-supporting, and in such a way as to avoid
becoming a nuisance or burden to his fellowmen, he escapes the
institutions for defectives and may pass for normal.
The most serious defect of the definition comes from the lax
interpretation of the term "ordinary prudence," etc. The popular
standard is so low that hundreds of thousands of high grade defectives
escape identification as such. Moreover, there are many grades of
severity in social and industrial competition. For example, most of the
members of such families as the Jukes, the Nams, the Hill Folk, and the
Kallikaks are able to pass as normal in their own crude environment, but
when compelled to compete with average American stock their deficiency
becomes evident. It is therefore necessary to supplement the social
criterion with a more strictly psychological one.
For this purpose there is nothing else as significant as the I Q. All
who test below 70 I Q by the Stanford revision of the Binet-Simon scale
should be considered feeble-minded, and it is an open question whether
it would not be justifiable to consider 75 I Q as the lower limit of
"normal" intelligence. Certainly a large proportion falling between
70 and 75 can hardly be classed as other than feeble-minded, even
according to the social criterion.
_Examples of feeble-minded school children_
_F. C. Boy, age 8-6; mental age 4-2; I Q approximately 50._ From
a very superior home. Has had the best medical care and other
attention. Attended a private kindergarten until rejected
because he required so much of the teacher's time and appeared
uneducable. Will probably develop to about the 6- or 7-year
mental level. High grade imbecile. Has since been committed to a
state institution. Cases as low as F. C. very rarely get into
the public schools.
_R. W. Boy, age 13-10; mental age 7-6; I Q approximately 55._
Home excellent. Is pubescent. Because of age and maturity has
been promoted to the third grade, though he can hardly do the
work of the second. Has attended school more than six years.
Will probably never develop much if any beyond 8 years, and will
never be self-supporting. Low-grade moron.
_M. S. Girl, age 7-6; mental age 4-6; I Q 60._ Father a
gardener, home conditions and medical attention fair. Has twice
attempted first grade, but without learning to read more than a
few words. In each case teacher requested parents to withdraw
her. "Takes" things. Is considered "foolish" by the other
children. Will probably never develop beyond a mental level of
_R. M. Boy, age 15; mental age 9; I Q 60._ Decidedly superior
home environment and care. After attending school eight years is
in fifth grade, though he cannot do the work of the fourth
grade. Parents unable to teach him to respect property. Boys
torment him and make his life miserable. At middle-moron level
and has probably about reached the limit of his development. Has
since been committed to a state institution.
_S. M. Girl, age 19-2; mental age 10; I Q approximately 65 (not
counting age beyond 16)._ From very superior family. Has
attended public and private schools twelve years and has been
promoted to seventh grade, where she cannot do the work. Appears
docile and childlike, but is subject to spells of disobedience
and stubbornness. Did not walk until 4 years old. Plays with
young children. Susceptible to attention from men and has to be
constantly guarded. Writing excellent, knows the number
combinations, but missed all the absurdities and has the
vocabulary of an average 10-year-old. The type from which
prostitutes often come.
_R. H. Boy, age 14; mental age 8-4; I Q 65._ Father Irish,
mother Spanish. Family comfortable and home care average. Has
attended school eight years and is unable to do fourth-grade
work satisfactorily. Health excellent and attendance regular.
Reads in fourth reader without expression and with little
comprehension of what is read. Fair skill in number
combinations. Writing and drawing very poor. Cannot use a ruler.
Has no conception of an inch.
R. H. is described as high-tempered, irritable, lacking in
physical activity, clumsy, and unsteady. Plays little. Just
"stands around." Indifferent to praise or blame, has little
sense of duty, plays underhand tricks. Is slow, absent-minded,
easily confused, in thought, never shows appreciation or
interest. So apathetic that he does not hear commands. Voice
droning. Speech poor in colloquial expressions.
Three years later, at age of 17, was in a special class
attempting sixth-grade work. Reported as doing "absolutely
nothing" in that grade. Still sullen, indifferent, and slow in
grasping directions, and lacking in play interests. "No
apperception of anything, but has mastered such mechanical
things as reading (calling the words) and the fundamentals in
In school work, moral traits, and out-of-school behavior R. H.
shows himself to be a typical case of moron deficiency.
_I. M. Girl, age 14-2; mental age 9; I Q approximately 65._
Father a laborer. Does unsatisfactory work in fourth grade.
Plays with little girls. A menace to the morals of the school
because of her sex interests and lack of self-restraint. Rather
good-looking if one does not hunt for appearances of
intelligence. Mental reactions intolerably slow. Will develop
but little further and will always pass as feeble-minded in any
but the very lowest social environment.
_G. V. Boy, age 10; mental age 6-4; I Q 65._ Father Spanish,
mother English. Family poor but fairly respectable. Brothers and
sisters all retarded. In high first grade. Work all very poor
except writing, drawing, and hand work, in all of which he
excels. Is quiet and inactive, lacks self-confidence, and plays
little. Mentally slow, inert, "thick," and inattentive. Health
Three years later G. V. was in the low third grade and still
doing extremely poor work in everything except manual training,
drawing, and writing. Is not likely ever to go beyond the fourth
or fifth grade however long he remains in school.
_V. J. Girl, age 11-6; mental age 8; I Q 70._ Has been tested
three times in the last five years, always with approximately
the same result in terms of I Q. Home fair to inferior. Has been
in a special class two years and in school altogether nearly six
years. Is barely able to do third-grade work. Her
feeble-mindedness is recognized by teachers and by other pupils.
Belongs at about middle-moron to high-moron level.
_A. W. Boy, age 9-4; mental age 7; I Q 75._ A year and a half
ago he tested at 6-2. From superior family, brothers of very
superior intelligence. In school three years and has made about
a grade and a half. Has higher I Q than V. J. described above,
but his deficiency is fully as evident. Is generally recognized
as mentally defective. Slyly abstracted one of the pennies used
in the test and slipped it into his pocket. Has caused much
trouble at school by puncturing bicycle tires. High-grade moron.
_A. C. Boy, age 12; mental age 8-5; I Q 70._ From Portuguese
family of ten children. Has a feeble-minded brother. Parents in
comfortable circumstances and respectable. A. C. has attended
school regularly since he was 6 years old. Trying unsuccessfully
to do the work of the fourth grade. Reads poorly in the third
reader. Hesitates, repeats, miscalls words, and never gets the
thought. Writes about like a first-grade pupil. Cannot solve
such simple problems as "How many marbles can you buy for ten
cents if one marble costs five cents?" even when he has marbles
and money in his hands. Described by teacher as "mentally slow
and inert, inattentive, easily distracted, memory poor, ideas
vague and often absurd, does not appreciate stories, slow at
comprehending commands." Is also described as "unruly,
boisterous, disobedient, stubborn, and lacking sense of
Three years later, at age of 15, was in a special class and was
little if any improved. He had, however, learned the mechanics
of reading and had mastered the number combinations.
Deficiencies described as "of wide range." Conduct, however, had
improved. Was "working hard to get on."
A. C. must be considered definitely feeble-minded.
_H. S. Boy, age 11; mental age 8-3; I Q approximately 75._ At
8 years tested at 6. Parents highly educated, father a scholar.
Brother and sister of very superior intelligence. Started to
school at 7, but was withdrawn because of lack of progress.
Started again at 8 and is now doing poor work in the second
grade. Weakly and nervous. Painfully aware of his inability to
learn. During the test keeps saying, "I tried anyway," "It's all
I can do if I try my best, ain't it?" etc. Regarded defective by
other children. Will probably never be able to do work beyond
the fourth or fifth grade and is not likely to develop above the
11-year level, if as high.
_I. S. Boy, age 9-6; mental age 7; I Q 75._ German parentage.
Started to school at 6. Now in low second grade and unable to do
the work. Health good. Inattentive, mentally slow and inert,
easily distracted, speech is monotone. Equally poor in reading,
writing, and numbers. I. S. is described as quiet, sullen,
indifferent, lazy, and stubborn. Plays little.
Three years later had advanced from low second to low fourth
grade, but was as poor as ever in his school work. "Miscalls the
simplest words." Moral traits unsatisfactory. May reach sixth or
seventh grade if he remains in school long enough.
I. S. learned to walk at 2 years and to talk at 3.
The above are cases of such marked deficiency that there could be no
disagreement among competent judges in classifying them in the group of
"feeble-minded." All are definitely institutional cases. It is a matter
of record, however, that one of the cases, H. S., was diagnosed by a
physician (without test) as "backward but not a defective." and with the
added encouragement that "the backwardness will be outgrown." Of course
the reverse is the case; the deficiency is becoming more and more
apparent as the boy approaches the age where more is expected of him.
In at least three of the above cases (S. M., I. S., and I. M.) the
teachers had not identified the backwardness as feeble-mindedness. Not
far from 2 children out of 100, or 2 out of 1000, in the average public
school are as defective as some of those just described. Teachers get so
accustomed to seeing a few of them in every group of 200 or 300 pupils
that they are likely to regard them as merely dull,--"dreadfully dull,"
of course,--but not defective.
Children like these, for their own good and that of other pupils, should
be kept out of the regular classes. They will rarely be equal to the
work of the fifth grade, however long they attend school. They will
make a little progress in a well-managed special class, but with the
approach of adolescence, at latest, the State should take them into
custodial care for its own protection.
Next: Border-line Cases (usually Between 70 And 80 I Q)
Previous: Classification Of Intelligence Quotients