The Measurement of Intelligence Part 21

"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 splas.h.i.+ng 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 fis.h.i.+ng."

"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 ap.r.o.n 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 a.s.sociation (combinative power) than mere enumeration. An unusually complete description indicates relative wealth of mental content and facility of a.s.sociation.

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. Pa.s.sed 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 repet.i.tion of digits differs from the repet.i.tion of sentences mainly in the fact that digits have less meaning (fewer a.s.sociations) 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 quant.i.tative 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.

Subst.i.tutions are also quite frequent, and if so many subst.i.tutions 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 repet.i.tion 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 s.h.i.+fted this test from year VII to year VIII. G.o.ddard 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 a.s.sert 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 pa.s.sed 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 pa.s.sed it. Only 35 per cent of the 6-year-olds succeeded, but after that age the per cent pa.s.sing 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 r.e.t.a.r.ded 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 ragam.u.f.fins, 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 a.s.sociative connections between successive motor coordinations (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 b.u.t.terfly?_" If the child does not seem to understand, say: "_You know flies, do you not? You have seen flies? And you know the b.u.t.terflies!

Now, tell me the difference between a fly and a b.u.t.terfly._" Proceed in the same way with _stone and egg_, and _wood and gla.s.s_. 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 b.u.t.terfly?_" This would give the child his cue and he would immediately answer, "A b.u.t.terfly." 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 b.u.t.terfly). It is then permissible to ask: "_Which is bigger?_"

SCORING. Pa.s.sed 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 b.u.t.terfly_

_Satisfactory._ "b.u.t.terfly is larger." "b.u.t.terfly has bigger wings." "Fly is black and a b.u.t.terfly is not." "b.u.t.terfly is yellow (or white, etc.) and fly is black." "Fly bites you and b.u.t.terfly don't." "b.u.t.terfly has powder on its wings, fly does not." "Fly flies straighter." "b.u.t.terfly is outdoors and a fly is in the house." "Flies are more dangerous to our health."

"Flies haven't anything to sip honey with." "b.u.t.terfly doesn't live as long as a fly." "b.u.t.terfly comes from a caterpillar."

Sometimes a double contrast is meant, but not fully expressed; as, "A fly is small and a b.u.t.terfly 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.