IntelligenceOther Fallacies In The Estimation Of Intelligence
Intelligence Tests Of Delinquents
The Validity Of The Intelligence Quotient
General Value Of The Method
How The Scale Is Used
Summary Of Changes
Alternative Test: Giving Age
Alternative Test: Repeating Twelve To Thirteen Syllables
Defining Abstract Words
Intelligence Tests Of Superior Children
The Ball-and-field Test (score 2 Inferior Plan)
Alternative Tests: Repeating Seven Digits
Tying A Bow-knot
Giving Similarities Three Things
Influence Of Social And Educational Advantages
Induction Test: Finding A Rule
Giving Differences From Memory
Giving Similarities; Two Things
PROCEDURE. Say to the child: "_I am going to name two things which are
alike in some way, and I want you to tell me how they are alike. Wood
and coal: in what way are they alike?_" Proceed in the same manner
_An apple and a peach._
_Iron and silver._
_A ship and an automobile._
After the first pair the formula may be abbreviated to "_In what way are
... and ... alike?_" It is often necessary to insist a little if the
child is silent or says he does not know, but in doing this we must
avoid supplementary questions and suggestions. In giving the first pair,
for example, it would not be permissible to ask such additional
questions as, "_What do you use wood for? What do you use coal for? And
now, how are wood and coal alike?_" This is really putting the answer in
the child's mouth. It is only permissible to repeat the original
question in a persuasive tone of voice, and perhaps to add: "_I'm sure
you can tell me how ... and ... are alike_," or something to that
A very common mistake which the child makes is to give differences
instead of similarities. This tendency is particularly strong if test 5,
year VII (giving differences), has been given earlier in the sitting,
but it happens often enough in other cases also to suggest that finding
differences is, to a much greater extent than finding similarities, the
child's preferred method of making a comparison. When a difference is
given, instead of a similarity, we say: "_No, I want you to tell me how
they are alike. In what way are ... and ... alike?_" Unless the child is
of rather low intelligence level this is sufficient, but the mentally
retarded sometimes continue to give differences persistently in spite
of repeated admonitions, or if they cease to do so for one or two
comparisons, they are likely to repeat the mistake in the latter part of
SCORING. The test is passed if a likeness is given in _two out of four_
comparisons. We accept as satisfactory any real likeness, whether
fundamental or superficial, though, of course, the more essential the
resemblance, the better indication it is of intelligence. The following
are samples of satisfactory and unsatisfactory answers:--
 For aid in classifying the responses in this and certain other
tests the writer is indebted to Miss Grace Lyman.
(a) _Wood and coal_
_Satisfactory._ "Both burn." "Both keep you warm." "Both are
used for fuel." "Both are vegetable matter." "Both come from the
ground." "Can use them both for running engines." "Both hard."
"Both heavy." "Both cost money."
Of 80 correct answers, 64, or 80 per cent, referred in one way
or another to combustibility.
_Unsatisfactory._ Most frequent is the persistent giving of a
difference instead of a similarity. This accounts for a little
over half of all the failures. About half of the remainder are
cases of inability to give any response. Incorrect statements
with regard to color are rather common. Sample failures of this
type are: "Both are black," or "Both the same color." Other
failures are: "Both are dirty on the outside;" "You can't break
them;" "Coal burns better;" "Wood is lighter than coal," etc.
(b) _An apple and a peach_
_Satisfactory._ "Both are round." "Both the same shape." "They
are about the same color." "Both nearly always have some red on
them." "Both good to eat." "Can make pies of both of them."
"Both can be cooked." "Both mellow when they are ripe." "Both
have a stem" (or seeds, skin, etc.). "Both come from trees."
"Can be dried in the same way." "Both are fruits." "Both green
(in color) when they are not ripe."
Of 82 correct answers, 25 per cent mention color; 25 per cent,
form; 22 per cent, edibility; 20 per cent, having stem, seed, or
skin; and 5 per cent, that both grow on trees.
_Unsatisfactory._ "Both taste the same." "Both have a lot of
seeds." "Both have a fuzzy skin." "An apple is bigger than a
peach." "One is red and one is white," etc.
Again, over 50 per cent of the failures are due to giving
differences and about 18 per cent to silence.
(c) _Iron and silver_
_Satisfactory._ "Both are metals" (or mineral). "Both come out
of the ground." "Both cost money." "Both are heavy." "Both are
hard." "Both can be melted." "Both can be bent." "Both used for
utensils." "You manufacture things out of both of them." "Both
can be polished."
These are named most frequently in the following order: (1)
hardness, (2) origin from the ground, (3) heaviness, (4) use in
_Unsatisfactory._ "Both thin" (or thick). "Sometimes they are
the same shape." "Both the same color." "A little silver and
lots of iron weigh the same." "Both made by the same company."
"They rust the same." "You can't eat them" (!)
 One is here reminded of the puzzling conundrum, "Why is a
brick like an elephant?" The answer being, "Because neither can
climb a tree!" A response of this type states a fact, but because
of its bizarre nature should hardly be counted satisfactory.
Of 60 failures, 32 were due to giving differences and 14 to
silence or unwillingness to hazard a reply.
(d) _A ship and an automobile_
_Satisfactory._ "Both means of travel." "Both go." "You ride in
them." "Both take you fast." "They both use fuel." "Both run by
machinery." "Both have a steering gear." "Both have engines in
them." "Both have wood in them." "Both can be wrecked." "Both
break if they hit a rock."
About 45 per cent of the answers are in terms of running or
travel, 37 per cent in terms of machinery or structure, the rest
_Unsatisfactory._ "Both black" (or some other color). "Both very
big." "They are made alike." "Both run on wheels." "Ship is for
the water and automobile for the land." "Ship goes on water and
an automobile sometimes goes in water." "An auto can go faster."
"Ship is run by coal and automobile by gasoline."
Of 51 failures, 32 were due to giving differences and 14 to
failure to reply.
REMARKS. The test of finding similarities was first used by Binet in
1905. Our results show that it is fully as satisfactory as the test of
giving differences. The test reveals in a most interesting way one of
the fundamental weaknesses of the feeble mind. Young normal children,
say of 7 or 8 years, often fail to pass, but it is the feeble-minded who
give the greatest number of absurd answers and who also find greatest
difficulty in resisting the tendency to give differences.
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