REMARKS. This test was first used by the writer in a comparative study of the intellectual processes of bright and dull boys in 1905, but it was not standardized until 1914. Rather extensive data indicate that it is a genuine test of intelligence. Of 14-year-old school children testing between 96 and 105 I Q, 59 per cent pa.s.sed this test; of 14-year-olds testing below 96 I Q, 41 per cent pa.s.sed; of those testing above 105, 71 per cent pa.s.sed. That is, the test agrees well with the results obtained by the scale as a whole. Of "average adults" only 10 per cent fail; and of "superior adults," fewer than 5 per cent. As a rule, the higher the grade of intelligence, the fewer the steps necessary for grasping the rule. Of the superior adults, only 35 per cent fail to get the rule as early as the end of the fourth step.

The test is little affected by schooling, and apart from differences in intelligence it is little influenced by age. Other advantages of the test are the keen interest it always arouses and its independence of language ability. It has been used successfully with immigrant subjects who had been in this country but a few months.

We have named the experiment an "induction test." It might be supposed that the solution would ordinarily be arrived at by deduction, or by an _a-priori_ logical a.n.a.lysis of the principle involved. This, however, is rarely the case. Not one average adult out of ten reasons out the situation in this purely logical manner. It is ordinarily only after one or more mistakes have been made and have been exposed by the examiner holding up the unfolded paper to view that the correct principle is grasped. In the absence of deductive reasoning the subject must note that each unfolded sheet contains twice as many holes as the previous one, and must infer that folding the paper again will again double the number. The ability tested is the ability to generalize from particulars where the common element of the particulars can be discerned only by the selective action of attention, in this case attention to the fact that each number is the double of its predecessor.

XIV, 3. GIVING DIFFERENCES BETWEEN A PRESIDENT AND A KING

PROCEDURE. Say: "_There are three main differences between a president and a king; what are they?_" If the subject stops after one difference is given, we urge him on, if possible, until three are given.

SCORING. The three differences relate to power, tenure, and manner of accession. Only these differences are considered correct, and the successful response must include at least two of the three. We disregard crudities of expression and note merely whether the subject has the essential idea. As regards power, for example, any of the following responses are satisfactory: "The king is absolute and the president is not." "The king rules by himself, but the president rules with the help of the people." "Kings can have things their own way more than presidents can," etc.

It may be objected that the reverse of this is sometimes true, that the king of to-day often has less power than the average president.

Sometimes subjects mention this fact, and when they do we credit them with this part of the test. As a matter of fact, however, this answer is seldom given.

Sometimes the subject does not stop until he has given a half-dozen or more differences, and in such cases the first three differences may be trivial and some of the later ones essential. The question then arises whether we should disregard the errors and pa.s.s the subject on his later correct responses. The rule in such cases is to ask the subject to pick out the "three main differences."

Sometimes accession and tenure are given in the form of a single contrast, as: "The president is elected, but the king inherits his throne and rules for life." This answer ent.i.tles the subject to credit for both accession and tenure, the contrast as regards tenure being plainly implied.

Unsatisfactory contrasts are of many kinds and are often amusing. Some of the most common are the following:--

"A king wears a crown." "A king has jewels." "A king sits on a throne." ("A king sets on a thorn" as one feeble-minded boy put it!) "A king lives in a palace." "A king has courtiers." "A king is very dignified." "A king dresses up more." "A president has less pomp and ceremony." "A president is more ready to receive the people." "A king sits on a chair all the time and a president does not." "No differences; it's just names." "A president does not give t.i.tles." "A king has a larger salary."

"A king has royal blood." "A king is in more danger." "They have a different t.i.tle." "A king is more cruel." "Kings have people beheaded." "A king rules in a monarchy and a president in a republic." "A king rules in a foreign country." "A president is elected and a king fights for his office." "A president appoints governors and a king does not." "A president lets the lawyers make the laws." "Everybody works for a king."

It is surprising to see how often trivial differences like the above are given. About thirty "average adults" out of a hundred, including high-school students, give at least one unsatisfactory contrast.

The test has been criticized as depending too much on schooling. The criticism is to a certain extent valid when the test is used with young subjects, say of 10 or 12 years. It is not valid, however, if the use of the test is confined to older subjects. With the latter, it is not a test of knowledge, but of the discriminative capacity to deal with knowledge already in the possession of the subject. It would be difficult to find an adult, not actually feeble-minded, who is ignorant of the facts called for: That the king inherits his throne, while the president is elected; that the tenure of the king is for life, and that of the president for a term of years; that kings ordinarily have, or are supposed to have, more power. Even the relatively stupid adult knows this; but he also knows that kings are different from presidents in having crowns, thrones, palaces, robes, courtiers, larger pay, etc., and he makes no discrimination as regards the relative importance of these differences.

The test is psychologically related to that of giving differences in year VII and to the two tests of finding similarities; but it differs from these in requiring a comparison based on fundamental rather than accidental distinctions. The idea is good and should be worked out in additional tests of the same type.

The test first appeared in the Binet revised scale of 1911. Kuhlmann omits it, and besides our own there are few statistics bearing on it.

Our results show that if two essential differences are required, the test belongs where we have placed it, but that if only one essential difference is required, the test is easy enough for year XII.

XIV, 4. PROBLEM QUESTIONS

PROCEDURE. Say to the subject: "_Listen, and see if you can understand what I read._" Then read the following three problems, rather slowly and with expression, pausing after each long enough for the subject to find an answer:--

(a) "_A man who was walking in the woods near a city stopped suddenly, very much frightened, and then ran to the nearest policeman, saying that he had just seen hanging from the limb of a tree a ... a what?_"

(b) "_My neighbor has been having queer visitors. First a doctor came to his house, then a lawyer, then a minister (preacher or priest). What do you think happened there?_"

(c) "_An Indian who had come to town for the first time in his life saw a white man riding along the street. As the white man rode by, the Indian said--'The white man is lazy; he walks sitting down.' What was the white man riding on that caused the Indian to say, 'He walks sitting down'?_"

Do not ask questions calculated to draw out the correct response, but wait in silence for the subject's spontaneous answer. It is permissible, however, to re-read the pa.s.sage if the subject requests it.

SCORING. _Two responses out of three must be satisfactory._ The following explanations and examples will make clear the requirements of the test:--

(a) _What the man saw hanging_

_Satisfactory._ The only correct answer for the first is "A man who had hung himself" (or who had committed suicide, been hanged, etc.). We may also pa.s.s the following answer: "Dead branches that looked like a man hanging."

A good many subjects answer simply, "A man." This answer cannot be scored because of the impossibility of knowing what is in the subject's mind, and in such cases it is always necessary to say: "_Explain what you mean._" The answer to this interrogation always enables us to score the response.

_Unsatisfactory._ There is an endless variety of failures: "A snake," "A monkey," "A robber," or "A tramp" being the most common. Others include such answers as "A bear," "A tiger," "A wild cat," "A cat," "A bird," "An eagle," "A bird's nest," "A hornet's nest," "A leaf," "A swing," "A boy in a swing," "A basket of flowers," "An egg," "A ghost," "A white sheet,"

"Clothes," "A purse," etc.

(b) _My neighbor_

_Satisfactory._ The expected answer is "A death," "Some one has died," etc. We must always check up this response, however, by asking what the lawyer came for, and this must also be answered correctly.

While it is expected that the subject will understand that the doctor came to attend a sick person, the lawyer to make his will, and the minister to preach the funeral, there are a few other ingenious interpretations which pa.s.s as satisfactory. For example, "A man got hurt in an accident; the doctor came to make him well, the lawyer to see about damages, and then he died and the preacher came for the funeral." Or, "A man died, the lawyer came to help the widow settle the estate and the preacher came for the funeral." We can hardly expect the 14-year-old child to know that it is not the custom to settle an estate until after the funeral.

The following excellent response was given by an enlightened young eugenist: "A marriage; the doctor came to examine them and see if they were fit to marry, the lawyer to arrange the marriage settlement, and the minister to marry them." The following logical responses occurred once each: "A murder. The doctor came to examine the body, the lawyer to get evidence, and the preacher to preach the funeral." "An unmarried girl has given birth to a child. The lawyer was employed to get the man to marry her and then the preacher came to perform the wedding ceremony." Perhaps some will consider this interpretation too far-fetched to pa.s.s. But it is perfectly logical and, unfortunately, represents an occurrence which is not so very rare.

If an incorrect answer is first given and then corrected, the correction is accepted.

_Unsatisfactory._ The failures again are quite varied, but are most frequently due to failure to understand the lawyer's mission. Of 66 tabulated failures, 26 are accounted for in this way, while only 6 are due to inability to state the part played by the minister. The most common incorrect responses are: "A baby born" (accounting for 5 out of 66 failures); "A divorce"

(very common with the children tested by Dr. Ordahl, at Reno, Nevada!); "A marriage"; "A divorce and a remarriage"; "A dinner"; "An entertainment"; "Some friends came to chat," etc.

In 20 failures out of 66, marriage was incorrectly connected with a will, a divorce, the death of a child, etc.

The following are not bad, but hardly deserve to pa.s.s: "Sickness and trouble; the lawyer and minister came to help him out of trouble." Or, "Somebody was sick; the lawyer wanted his money and the minister came to see how he was." A few present a still more logical interpretation, but so far-fetched that it is doubtful whether they should count as pa.s.ses; for example: "A man and his wife had a fight. One got hurt and had to have the doctor, then they had a lawyer to get them divorced, then the minister came to marry one of them." Again, "Some one is dying and is getting married and making his will before he dies."

(c) _What the man was riding on_

The only correct response is "Bicycle." The most common error is _horse_ (or _donkey_), accounting for 48 out of 71 tabulated failures. Vehicles, like _wagon_, _buggy_, _automobile_, or _street car_, were mentioned in 14 out of 71 failures. Bizarre replies are: "A cripple in a wheel chair"; "A person riding on some one's back," etc.

REMARKS. The experiment is a form of the completion test. Elements of a situation are given, out of which the entire situation is to be constructed. This phase of intelligence has already been discussed.[74]

[74] See IX, 5, and XII, 4.

While it is generally admitted that the underlying idea of this test is good, some have criticized Binet's selection of problems. Meumann thinks the lawyer element of the second is so unfamiliar to children as to render that part of the test unfair. Several "armchair" critics have mentioned the danger of nervous shock from the first problem. Bobertag throws out the test entirely and subst.i.tutes a completion test modeled after that of Ebbinghaus. Our own results are altogether favorable to the test. If it is used in year XIV, Meumann's objection hardly holds, for American children of that age do ordinarily know something about making wills. As for the danger of shock from the first problem, we have never once found the slightest evidence of this much-feared result. The subject always understands that the situation depicted is hypothetical, and so answers either in a matter-of-fact manner or with a laugh.

The bicycle problem is our own invention. Binet used the other two and required both to be answered correctly. The test was located in year XII of the 1908 scale, and in year XV of the 1911 revision. G.o.ddard and Kuhlmann retain it in the original location. The Stanford results of 1911, 1912, 1914, and 1915 agree in showing the test too difficult for year XII, even when only two out of three correct responses are required. If the original form of the experiment is used, it is exceedingly difficult for year XV. As here given it fits well at year XIV.

XIV, 5. ARITHMETICAL REASONING

PROCEDURE. The following problems, printed in clear type, are shown one at a time to the subject, who reads each problem aloud and (with the printed problem still before him) finds the answer without the use of pencil or paper.

(a) _If a man's salary is $20 a week and he spends $14 a week, how long will it take him to save $300?_ (b) _If 2 pencils cost 5 cents, how many pencils can you buy for 50 cents?_ (c) _At 15 cents a yard, how much will 7 feet of cloth cost?_

Only one minute is allowed for each problem, but nothing is said about hurrying. While one problem is being solved, the others should be hidden from view. It is not permissible, if the subject gives an incorrect answer, to ask him to solve the problem again. The following exception, however, is made to this rule: If the answer given to the third problem indicates that the word _yard_ has been read as _feet_, the subject is asked to read the problem through again carefully (aloud) and to tell how he solved it. No further help of any kind may be given.

SCORING. _Two of the three_ problems must be solved correctly within the minute allotted to each. No credit is allowed for correct method if the answer is wrong.

REMARKS. We have selected these problems from the list used by Bonser in his _Study of the Reasoning Ability of Children in the Fourth, Fifth, and Sixth School Grades_.[75]

[75] Columbia University Contributions to Education, no. 37, 1910.