The Measurement of Intelligence
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Lewis Madison Terman >> The Measurement of Intelligence
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Sentences of sixteen syllables found a place in Binet's 1908 scale and
were correctly located in year VI, but later revisions, including that
of Binet, have omitted the test.
VI. ALTERNATIVE TEST: FORENOON AND AFTERNOON
PROCEDURE. If it is morning, ask: "_Is it morning or afternoon?_" If it
is afternoon, put the question in the reverse form, "_Is it afternoon or
morning?_" This precaution is necessary because of the tendency of some
children to choose always the latter of two alternatives. Do not
cross-question the child or give any suggestion that might afford a clue
as to the correct answer.
SCORING. The test is passed if the correct response is given with
apparent assurance. If the child says he is not sure but _thinks_ it
forenoon (or afternoon, as the case may be), we score the response a
failure even if the answer happens to be correct. However, this type of
response is not often encountered.
REMARKS. It is interesting to follow the child's development with regard
to orientation in time. This development proceeds much more slowly than
we are wont to assume. Certain distinctions with regard to space, as up
and down, come much earlier. As Binet remarks, schools sometimes try to
teach the events of national history to children whose time orientation
is so rudimentary that they do not even know morning from afternoon!
The test has two rather serious faults: (1) It gives too much play to
chance, for since only two alternatives are offered, guesses alone would
give about fifty per cent of correct responses. (2) We cannot be sure
that the verbal distinction between forenoon and afternoon always
corresponds the two divisions of the day. It is possible that the
temporal discrimination precedes the formation of the correct verbal
association.
This test was included in the year VI group of the 1908 scale, but was
omitted from the 1911 revision. Nearly all the data except Bobertag's
show that it is rather easy for year VI, though too difficult for
year V. Bobertag's figures would place the test in year VII. Possibly
the corresponding German words are not as easy to learn as our _morning_
and _afternoon_.
CHAPTER XIII
INSTRUCTIONS FOR YEAR VII
VII, 1. GIVING THE NUMBER OF FINGERS
PROCEDURE. "_How many fingers have you on one hand?_" "_How many on the
other hand?_" "_How many on both hands together?_" If the child begins
to count in response to any of the questions, say: "_No, don't count.
Tell me without counting._" Then repeat the question.
SCORING. Passed _if all three questions are answered correctly and
promptly_ without the necessity of counting. Some subjects do not
understand the question to include the thumbs. We disregard this if the
number of fingers exclusive of thumbs is given correctly.
REMARKS. Like the two tests of counting pennies, this one, also, throws
light on the child's spontaneous interest in numbers. However, the
mental processes it calls into play are a little less simple than those
required for mere counting. If the child is able to give the number of
fingers, it is ordinarily because he has previously counted them and has
remembered the result. The memory would hardly be retained but for a
certain interest in numbers as such. Middle-grade imbeciles of even
adult age seldom remember how many fingers they have, however often
they may have been told. They are not able to form accurate concepts of
other than the simplest number relationships, and numbers have little
interest or meaning for them.
Binet gave this test a place in year VII of the 1908 series, but omitted
it in the 1911 revision. Goddard omits it, while Kuhlmann retains it in
year VII, where, according to our own figures, it unmistakably belongs.
Bobertag finds it rather easy for year VII, though too difficult for
year VI.
Our data prove that this test fulfills the requirements of a good test.
It shows a rapid but even rise from year V to year VIII in the per cent
passing, the agreement among the different testers is extraordinarily
close, and it is relatively little influenced by training and social
environment. For these reasons, and because it is so easy to give and
score with uniformity, it well deserves a place in the scale.
VII, 2. DESCRIPTION OF PICTURES
PROCEDURE. Use the same pictures as in III, 3, presenting them always in
the following order: Dutch Home, River Scene, Post-Office. The formula
for the test in this year is somewhat different from that of year III.
Say: "_What is this picture about? What is this a picture of?_" Use the
double question, and follow the formula exactly. It would ruin the test
to say: "_Tell me everything you see in this picture_," for this form of
question tends to provoke the enumeration response even with intelligent
children of this age.
When there is no response, the question may be repeated as often as is
necessary to break the silence.
SCORING. The test is passed if _two of the three_ pictures are described
or interpreted. Interpretation, however, is seldom encountered at this
age. Often the response consists of a mixture of enumeration and
description. The rule is that the reaction to a picture should not
be scored _plus_ unless it is made up chiefly of description (or
interpretation).
Study of the following samples of satisfactory responses will give a
fairly definite idea of the requirements for satisfactory description:--
_Picture (a): satisfactory responses_
"The little girl is crying. The mother is looking at her and
there is a little kitten on the floor."
"The mother is watching the baby, and the cat is looking at a
hole in the floor, and there is a lamp and a table so I guess
it's a dining room."
"The little girl has wooden shoes. Her mother is sitting in a
chair and has a funny cap on her head. The cat is sitting on the
floor and there is a basket by the mother and a table with
something on it."
"It's about Holland. The little Dutch girl is crying and the
mother is sitting down."
"A little Dutch girl and her mother and that's a kitten, and the
little girl has her hand up as if she was doing something to her
forehead. She has shoes that curve up in front."
"Dutch lady, and the little baby doesn't want to come to her
mother and the cat is looking for some mice."
"The mother is sitting down and the little one has her hands up
over her eyes. There's a pail by the mother and a chair with
some clothes on it and a table with dishes. And here's a lamp
and here's some curtains."
_Picture (b): satisfactory responses_
"Some people in a boat. The water is high and if they don't look
out the boat will tip over."
"Some Indians and a lady and man. They are in a boat on the
river and the boat is about to upset, and there are some dead
trees going to fall."
"There's a lot of water coming up to drown the people. There are
two people in the boat and the boat is sinking."
"There's some people sailing in a canoe and the woman is leaning
over on the man because she is afraid."
"There's an Indian and some white people in the boat. I suppose
they are out for a ride in a canoe."
"Picture about some man and lady in a canoe and going down to
the sea."
"They are taking a boat ride on the ocean and the water is up so
high that one of them is scared. Here are some trees and two of
them are going to fall down. Here's a little place or bridge you
can stand on. The man is touching this one's head and this one
has his hand on the cover."
"The water is splashing all over. There's trees on this bank and
there's a rock and some trees falling down. The people have a
blanket over them."
_Picture (c): satisfactory responses_
"A man selling eggs and two men reading the paper together and
two men watching."
"A few men reading a newspaper and one has a basket of eggs and
this one has been fishing."
"There's a man with a basket of eggs and another is reading the
paper and a woman is hanging out clothes. There's a house near."
"There's a man trying to read the paper and the others want to
read it too. Here's a lady walking up to the barn. There are
houses over there and one man has a basket."
"There's a big brick house and five men by it and a man with a
basket of eggs and a post-office sign and a lady going home."
"They are all looking at the paper. He is looking over the other
man's shoulder and this one is looking at the back of the paper.
There's a woman cleaning up her back yard and some coops for
hens."
"A man reading a paper, a man with eggs, a woman and a tree and
another house. That man has an apron on. This is the
post-office."
Unsatisfactory responses are those made up entirely or mainly of
enumeration. A phrase or two of description intermingled with a larger
amount of enumeration counts _minus_. Sometimes the description is
satisfactory as far as it goes, but is exceedingly brief. In such cases
a little tactful urging ("_Go ahead_," etc.) will extend the response
sufficiently to reveal its true character.
REMARKS. Description is better than enumeration because it involves
putting the elements of a picture together in a simple way or noting
their qualities. This requires a higher type of mental association
(combinative power) than mere enumeration. An unusually complete
description indicates relative wealth of mental content and facility of
association.
Binet placed this test in year VII, and it seems to have been retained
in this location in all revisions except Bobertag's. However, the
statistics of various workers show much disagreement. Lack of agreement
is easily accounted for by the fact that different investigators have
used different series of pictures and doubtless also different standards
for success. The pictures used by Binet have little action or detail and
are therefore rather difficult for description. On the other hand, the
Jingleman-Jack pictures used by Kuhlmann represent such familiar
situations and have so much action that even 5- or 6-year intelligence
seldom fails with them. The pictures we employ belong without question
in year VII.
No better proof than the above could be found to show how ability of a
given kind does not make its appearance suddenly. There is no one time
in the life of even a single child when the power to describe pictures
suddenly develops. On the contrary, pictures of a certain type will
ordinarily provoke description, rather than enumeration, as early as
5 or 6 years; others not before 7 or 8 years, or even later.
VII, 3. REPEATING FIVE DIGITS
PROCEDURE. Use: 3-1-7-5-9; 4-2-3-8-5; 9-8-1-7-6. Tell the child to
listen and to say after you just what you say. Then read the first
series of digits at a slightly faster rate than one per second, in a
distinct voice, and with perfectly uniform emphasis. _Avoid rhythm._
In previous tests with digits, it was permissible to re-read the first
series if the child refused to respond. In this year, and in the digits
tests of later years, this is not permissible. Warning is not given as
to the number of digits to be repeated. Before reading each series, get
the child's attention. Do not stare at the child during the response, as
this is disconcerting. Look aside or at the record sheet.
SCORING. Passed if the child repeats correctly, after a single reading,
_one series out of the three_ series given. The order must be correct.
REMARKS. Psychologically the repetition of digits differs from the
repetition of sentences mainly in the fact that digits have less meaning
(fewer associations) than the words of a sentence. It is because they
are not as well knit together in meaning that three digits tax the
memory as much as six syllables making up a sentence.
Testing auditory memory for digits is one of the oldest of intelligence
tests. It is easy to give and lends itself well to exact quantitative
standardization. Its value has been questioned, however, on two grounds:
(1) That it is not a test of pure memory, but depends largely on
attention; and (2) that the results are too much influenced by the
child's type of imagery. As to the first objection, it is true that more
than one mental function is brought into play by the test. The same may
be said of every other test in the Binet scale and for that matter of
any test that could be devised. It is impossible to isolate any function
for separate testing. In fact, the functions called memory, attention,
perception, judgment, etc., never operate in isolation. There are no
separate and special "faculties" corresponding to such terms, which are
merely convenient names for characterizing mental processes of various
types. In any test it is "general ability" which is operative, perhaps
now _chiefly_ in remembering, at another time _chiefly_ in sensory
discrimination, again in reasoning, etc.
The second objection, that the test is largely invalidated by the
existence of imagery types, is not borne out by the facts. Experiments
have shown that pure imagery types are exceedingly rare, and that
children, especially, are characterized by "mixed" imagery. There are
probably few subjects so lacking in auditory imagery as to be placed at
a serious disadvantage in this test.
Lengthening a series by the addition of a single digit adds greatly to
the difficulty. While four digits can usually be repeated by children of
4 years, five digits belong in year VII and six in year X.
It is always interesting to note the type of errors made. The most
common error is to omit one or more of the digits, usually in the first
part of the series. If the child's ability is decidedly below the test
he may give only the last two or three out of the five or six heard.
Substitutions are also quite frequent, and if so many substitutions are
made as to give a series quite unlike that which the child has heard, it
is an unfavorable sign, indicating weakness of the critical sense which
is so often found with low-level intelligence. In case of extreme
weakness of the power of auto-criticism, the child in response to the
series 9-8-1-7-6-, may say 1-2-3-4-5-6, or perhaps merely a couple of
digits like 8-6, and still express complete satisfaction with his absurd
response. After each series, therefore, the examiner should say, "_Was
it right?_"[54] Very young subjects, however, have a tendency to answer
"yes" to any question of this type, and it is therefore best not to call
for criticism of a performance below the age of 6 or 7 years.
[54] "_Was it wrong?_" is not an equivalent question and should not be
used.
Digit series of a given length are not always of equal difficulty, and
for this reason it is never wise to use series improvised at the moment
of the experiment. We must avoid especially series of regularly
ascending or descending value, the repetition at regular intervals of a
particular digit, and all other peculiarities of arrangement which would
favor the grouping of the digits for easier retention.
It remains to mention two or three further cautions in regard to
procedure. It is best to begin with a series about one digit below the
child's expected ability. If the child has a probable intelligence of
about 6 or 7 years, we should begin with four digits; in case of
probable 10-year intelligence we begin with five digits, etc. On the
other hand, we should avoid beginning too far down, because then the
result is too much complicated by the effects of practice and fatigue.
It is not necessary, and often it is not expedient, to give the digits
tests of all the different years in succession; that is, without other
tests intervening. While this may be permissible with older children, in
young children the power of sustained attention is so weak that no
single kind of test should occupy more than two or three minutes.
Children below 6 or 7 years should ordinarily be given the tests in the
order in which they are listed in the record booklet.
In his 1911 revision of the scale Binet unfortunately shifted this test
from year VII to year VIII. Goddard follows his example, but Kuhlmann
retains it in year VII. The data from more than a dozen leading
investigations in America, England, and Germany agree in showing that
the test should remain in year VII.
VII, 4. TYING A BOW-KNOT
PROCEDURE. Prepare a shoestring tied in a bow-knot around a stick. The
knot should be an ordinary "double bow," with wings not over three or
four inches long. Make this ready in advance of the experiment and show
the child only the completed knot.
Place the model before the subject with the wings pointing to the right
and left, and say: "_You know what kind of knot this is, don't you? It
is a bow-knot. I want you to take this other piece of string and tie the
same kind of knot around my finger._" At the same time give the child a
piece of shoestring, of the same length as that which is tied around the
stick, and hold out a finger pointed toward the child and in convenient
position for the operation. It is better to have the subject tie the
string around the examiner's finger than around a pencil or other object
because the latter often falls out of the string and is otherwise
awkward to handle.
Some children who assert that they do not know how to tie a bow-knot are
sometimes nevertheless successful when urged to try. It is always
necessary, therefore, to secure an actual trial.
SCORING. The test is passed if a double bow-knot (both ends folded in)
is made _in not more than a minute_. A single bow-knot (only one end
folded in) counts half credit, because children are often accustomed to
use the single bow altogether. The usual plain common knot, which
precedes the bow-knot proper, must not be omitted if the response is to
count as satisfactory, for without this preliminary plain knot a
bow-knot will not hold and is of no value. To be satisfactory the knot
should also be drawn up reasonably close, not left gaping.
REMARKS. This test, which had not before been standardized, was
suggested to the writer by the late Dr. Huey, who in a conversation
once remarked upon the frequent inability of feeble-minded adults to
perform the little motor tasks which are universally learned by normal
persons in childhood. The test was therefore incorporated in the
Stanford trial series of 1913-14 and tried with 370 non-selected
children within two months of the 6th, 7th, 8th, or 9th birthday. It was
expected that the test would probably be found to belong at about the
8-year level, but it proved to be easy enough for year VII, where
69 per cent of the children passed it. Only 35 per cent of the
6-year-olds succeeded, but after that age the per cent passing increased
rapidly to 94 per cent at 9 years.
This little experiment, simple as it is, seems to fulfill reasonably
well the requirements of a good test. The main objection which might be
brought against it is that it is much subject to the influence of
training. If this were true in any marked degree, the mentally retarded
children of 7-year intelligence should be expected to succeed better
with it than mentally advanced children of the same mental level, since
the former would have had at least two or three years more in which to
learn the task. A comparison of the two groups, however, shows no great
difference. The factor of age, apart from mental age, affects the
results so little that it is evident we have here a real test of
intelligence.
It would, of course, be easy to imagine a child of 7 years who had not
had reasonable opportunity to make the acquaintance of bow-knots or to
learn to tie them. But such children are seldom encountered in the ages
above 6 or 7. Of 68 7-year-olds who were asked whether they had ever
seen a bow-knot ("a knot like that") only two replied in the negative.
It cannot be denied, however, that specific instruction and special
stimulus to practice do play a certain part. This is suggested by the
fact that girls excel the boys somewhat at each age, doubtless because
bow-knots play a larger role in feminine apparel. Social status affects
the results in only a moderate degree, though it might be supposed that
poor ragamuffins, on the one hand, and children of the very rich, on the
other, would both make a poor showing in this test; the former because
of their scanty apparel, the latter because they sometimes have servants
to dress them.
The following are probably the chief factors determining success with
this test: (1) Interest in common objective things; (2) ability to form
permanent associative connections between successive motor cooerdinations
(memory for a series of acts); and (3) skill in the acquisition of
voluntary motor control. The last factor is probably much less important
than the other two. Motor awkwardness often prolongs the time from the
usual ten or fifteen seconds to thirty or forty seconds, but it is
rarely a cause of a failure. The important thing is to be able to
reproduce the appropriate succession of acts, acts which nearly all
children of 7 years, under the joint stimulus of example and spontaneous
interest, have before performed or tried to perform.
VII, 5. GIVING DIFFERENCES FROM MEMORY
PROCEDURE. Say: "_What is the difference between a fly and a
butterfly?_" If the child does not seem to understand, say: "_You know
flies, do you not? You have seen flies? And you know the butterflies!
Now, tell me the difference between a fly and a butterfly._" Proceed in
the same way with _stone and egg_, and _wood and glass_. A little
coaxing is sometimes necessary to secure a response, but supplementary
questions and suggestions of every kind are to be avoided. For example,
it would not be permissible for the examiner to say: "_Which is larger,
a fly or a butterfly?_" This would give the child his cue and he would
immediately answer, "A butterfly." The child must be left to find a
difference by himself. Sometimes a difference is given, but without any
indication as to its direction, as, for example, "One is bigger than the
other" (for fly and butterfly). It is then permissible to ask: "_Which
is bigger?_"
SCORING. Passed if a real difference is given in _two out of three
comparisons_. It is not necessary, however, that an _essential_
difference be given; the difference may be trivial, only it must be a
real one. The following are samples of satisfactory and unsatisfactory
responses:--
_Fly and butterfly_
_Satisfactory._ "Butterfly is larger." "Butterfly has bigger
wings." "Fly is black and a butterfly is not." "Butterfly is
yellow (or white, etc.) and fly is black." "Fly bites you and
butterfly don't." "Butterfly has powder on its wings, fly does
not." "Fly flies straighter." "Butterfly is outdoors and a fly
is in the house." "Flies are more dangerous to our health."
"Flies haven't anything to sip honey with." "Butterfly doesn't
live as long as a fly." "Butterfly comes from a caterpillar."
Sometimes a double contrast is meant, but not fully expressed;
as, "A fly is small and a butterfly is pretty." Here the thought
is probably correct, only the language is awkward.
Of 102 correct responses, 70 were in terms of size, or size plus
color or form; 12 were in terms of both form and color; 6 in
terms of color alone; and the rest scattered among such
responses as those mentioned above.
_Unsatisfactory._ These are mostly misstatements of facts; as:
"Fly is bigger." "Fly has legs and butterfly hasn't." "Butterfly
has no feet and fly has." "Butterfly makes butter." "Fly is a
fly and a butterfly is not." Failures due to misstatement of
fact are of endless variety. If an indefinite response is given,
like "The fly is different," or "They don't look alike," we ask,
"_How is it different?_" or, "_Why don't they look alike?_" It
is satisfactory if the child then gives a correct answer.
_Stone and egg_
_Satisfactory._ "Stone is harder." "Egg is softer." "Egg breaks
easier." "Egg breaks and stone doesn't." "Stone is heavier."
"Egg is white and stone is not." "Egg has a shell and stone does
not." "Eggs have a white and a yellow in them." "You put eggs in
a pudding." "An egg is rounder than a stone." We may also accept
statements which are only qualifiedly true; as, "You can break
an egg, but not a stone." Likewise double but incomplete
comparisons are satisfactory; as, "An egg you fry and a stone
you throw," "A stone is tough and an egg you eat," etc.
A little over three fourths of the comparisons made by children
of 6, 7, and 8 years are in terms of hardness. The other
responses are widely scattered.
_Unsatisfactory._ "A stone is bigger (or smaller) than an egg."
"A stone is square and an egg is round." "An egg is yellow and a
stone is white." "Stones are red (or black, etc.) and eggs are
white." "An egg is to eat and a stone is to plant." "An egg is
round and a stone is sometimes round."
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