The Measurement of Intelligence Part 4

4. Counts thirteen pennies.

5. Distinguishes pictures of ugly and pretty faces.

_Age 7:_ 1. Shows right hand and left ear.

2. Describes a picture.

3. Executes three commissions, given simultaneously.

4. Counts the value of six sous, three of which are double.

5. Names four cardinal colors.

_Age 8:_ 1. Compares two objects from memory.

2. Counts from 20 to 0.

3. Notes omissions from pictures.

4. Gives day and date.

5. Repeats five digits.

_Age 9:_ 1. Gives change from twenty sous.

2. Defines familiar words in terms superior to use.

3. Recognizes all the pieces of money.

4. Names the months of the year, in order.

5. Answers easy "comprehension questions."

_Age 10:_ 1. Arranges five blocks in order of weight.

2. Copies drawings from memory.

3. Criticizes absurd statements.

4. Answers difficult "comprehension questions."

5. Uses three given words in not more than two sentences.

_Age 12:_ 1. Resists suggestion.

2. Composes one sentence containing three given words.

3. Names sixty words in three minutes.

4. Defines certain abstract words.

5. Discovers the sense of a disarranged sentence.

_Age 15:_ 1. Repeats seven digits.

2. Finds three rhymes for a given word.

3. Repeats a sentence of twenty-six syllables.

4. Interprets pictures.

5. Interprets given facts.

_Adult:_ 1. Solves the paper-cutting test.

2. Rearranges a triangle in imagination.

3. Gives differences between pairs of abstract terms.

4. Gives three differences between a president and a king.

5. Gives the main thought of a selection which he has heard read.

It should be emphasized that merely to name the tests in this way gives little idea of their nature and meaning, and tells nothing about Binet's method of conducting the 54 experiments. In order to use the tests intelligently it is necessary to acquaint one's self thoroughly with the purpose of each test, its correct procedure, and the psychological interpretation of different types of response.[10]

[10] See Part II of this volume, and References 1 and 29, for discussion and interpretation of the individual tests.

In fairness to Binet, it should also be borne in mind that the scale of tests was only a rough approximation to the ideal which the author had set himself to realize. Had his life been spared a few years longer, he would doubtless have carried the method much nearer perfection.

HOW THE SCALE IS USED. By means of the Binet tests we can judge the intelligence of a given individual by comparison with standards of intellectual performance for normal children of different ages. In order to make the comparison it is only necessary to begin the examination of the subject at a point in the scale where all the tests are pa.s.sed successfully, and to continue up the scale until no more successes are possible. Then we compare our subject's performances with the standard for normal children of the same age, and note the amount of acceleration or r.e.t.a.r.dation.

Let us suppose the subject being tested is 9 years of age. If he goes as far in the tests as normal 9-year-old children ordinarily go, we can say that the child has a "mental age" of 9 years, which in this case is normal (our child being 9 years of age). If he goes only as far as normal 8-year-old children ordinarily go, we say that his "mental age"

is 8 years. In like manner, a mentally defective child of 9 years may have a "mental age" of only 4 years, or a young genius of 9 years may have a mental age of 12 or 13 years.

SPECIAL CHARACTERISTICS OF THE BINET-SIMON METHOD. Psychologists had experimented with intelligence tests for at least twenty years before the Binet scale made its appearance. The question naturally suggests itself why Binet should have been successful in a field where previous efforts had been for the most part futile. The answer to this question is found in three essential differences between Binet's method and those formerly employed.

1. _The use of age standards._ Binet was the first to utilize the idea of age standards, or norms, in the measurement of intelligence. It will be understood, of course, that Binet did not set out to invent tests of 10-year intelligence, 6-year intelligence, etc. Instead, as already explained, he began with a series of tests ranging from very easy to very difficult, and by trying these tests on children of different ages and noting the percentages of successes in the various years, he was able to locate them (approximately) in the years where they belonged.

This plan has the great advantage of giving us standards which are easily grasped. To say, for ill.u.s.tration, that a given subject has a grade of intelligence equal to that of the average child of 8 years is a statement whose general import does not need to be explained. Previous investigators had worked with subjects the degree of whose intelligence was unknown, and with tests the difficulty of which was equally unknown.

An immense amount of ingenuity was spent in devising tests which were used in such a way as to preclude any very meaningful interpretation of the responses.

The Binet method enables us to characterize the intelligence of a child in a far more definite way than had hitherto been possible. Current descriptive terms like "bright," "moderately bright," "dull," "very dull," "feeble-minded," etc., have had no universally accepted meaning.

A child who is designated by one person as "moderately bright" may be called "very bright" by another person. The degree of intelligence which one calls "moderate dullness," another may call "extreme dullness," etc.

But every one knows what is meant by the term 8-year mentality, 4-year mentality, etc., even if he is not able to define these grades of intelligence in psychological terms; and by ascertaining experimentally what intellectual tasks children of different ages can perform, we are, of course, able to make our age standards as definite as we please.

Why should a device so simple have waited so long for a discoverer? We do not know. It is of a cla.s.s with many other unaccountable mysteries in the development of scientific method. Apparently the idea of an age-grade method, as this is called, did not come to Binet himself until he had experimented with intelligence tests for some fifteen years. At least his first provisional scale, published in 1905, was not made up according to the age-grade plan. It consisted merely of 30 tests, arranged roughly in order of difficulty. Although Binet nowhere gives any account of the steps by which this crude and ungraded scale was transformed into the relatively complete age-grade scale of 1908, we can infer that the original and ingenious idea of utilizing age norms was suggested by the data collected with the 1905 scale. However the discovery was made, it ranks, perhaps, from the practical point of view, as the most important in all the history of psychology.

2. _The kind of mental functions brought into play._ In the second place, the Binet tests differ from most of the earlier attempts in that they are designed to test the higher and more complex mental processes, instead of the simpler and more elementary ones. Hence they set problems for the reasoning powers and ingenuity, provoke judgments about abstract matters, etc., instead of attempting to measure sensory discrimination, mere retentiveness, rapidity of reaction, and the like.

Psychologists had generally considered the higher processes too complex to be measured directly, and accordingly sought to get at them indirectly by correlating supposed intelligence with simpler processes which could readily be measured, such as reaction time, rapidity of tapping, discrimination of tones and colors, etc. While they were disputing over their contradictory findings in this line of exploration, Binet went directly to the point and succeeded where they had failed.

It is now generally admitted by psychologists that higher intelligence is little concerned in such elementary processes as those mentioned above. Many of the animals have keen sensory discrimination.

Feeble-minded children, unless of very low grade, do not differ very markedly from normal children in sensitivity of the skin, visual acuity, simple reaction time, type of imagery, etc. But in power of comprehension, abstraction, and ability to direct thought, in the nature of the a.s.sociative processes, in amount of information possessed, and in spontaneity of attention, they differ enormously.

3. _Binet would test "general intelligence."_ Finally, Binet's success was largely due to his abandonment of the older "faculty psychology"

which, far from being defunct, had really given direction to most of the earlier work with mental tests. Where others had attempted to measure memory attention, sense discrimination, etc., as separate faculties or functions, Binet undertook to ascertain the _general level_ of intelligence. Others had thought the task easier of accomplishment by measuring each division or aspect of intelligence separately, and summating the results. Binet, too, began in this way, and it was only after years of experimentation by the usual methods that he finally broke away from them and undertook, so to speak, to triangulate the height of his tower without first getting the dimensions of the individual stones which made it up.

The a.s.sumption that it is easier to measure a part, or one aspect, of intelligence than all of it, is fallacious in that the parts are not separate parts and cannot be separated by any refinement of experiment.

They are interwoven and intertwined. Each ramifies everywhere and appears in all other functions. The a.n.a.logy of the stones of the tower does not really apply. Memory, for example, cannot be tested separately from attention, or sense-discrimination separately from the a.s.sociative processes. After many vain attempts to disentangle the various intellective functions, Binet decided to test their combined functional capacity without any pretense of measuring the exact contribution of each to the total product. It is hardly too much to say that intelligence tests have been successful just to the extent to which they have been guided by this aim.

Memory, attention, imagination, etc., are terms of "structural psychology." Binet's psychology is dynamic. He conceives intelligence as the sum total of those thought processes which consist in mental adaptation. This adaptation is not explicable in terms of the old mental "faculties." No one of these can explain a single thought process, for such process always involves the partic.i.p.ation of many functions whose separate roles are impossible to distinguish accurately. Instead of measuring the intensity of various mental states (psycho-physics), it is more enlightening to measure their combined effect on adaptation. Using a biological comparison, Binet says the old "faculties" correspond to the separate tissues of an animal or plant, while his own "scheme of thought" corresponds to the functioning organ itself. For Binet, psychology is the science of behavior.

BINET'S CONCEPTION OF GENERAL INTELLIGENCE. In devising tests of intelligence it is, of course, necessary to be guided by some a.s.sumption, or a.s.sumptions, regarding the nature of intelligence. To adopt any other course is to depend for success upon happy chance.

However, it is impossible to arrive at a final definition of intelligence on the basis of _a-priori_ considerations alone. To demand, as critics of the Binet method have sometimes done, that one who would measure intelligence should first present a complete definition of it, is quite unreasonable. As Stern points out, electrical currents were measured long before their nature was well understood. Similar ill.u.s.trations could be drawn from the processes involved in chemistry physiology, and other sciences. In the case of intelligence it may be truthfully said that no adequate definition can possibly be framed which is not based primarily on the symptoms empirically brought to light by the test method. The best that can be done in advance of such data is to make tentative a.s.sumptions as to the probable nature of intelligence, and then to subject these a.s.sumptions to tests which will show their correctness or incorrectness. New hypotheses can then be framed for further trial, and thus gradually we shall be led to a conception of intelligence which will be meaningful and in harmony with all the ascertainable facts.

Such was the method of Binet. Only those unacquainted with Binet's more than fifteen years of labor preceding the publication of his intelligence scale would think of accusing him of making no effort to a.n.a.lyze the mental processes which his tests bring into play. It is true that many of Binet's earlier a.s.sumptions proved untenable, and in this event he was always ready, with exceptional candor and intellectual plasticity, to acknowledge his error and to plan a new line of attack.

Binet's conception of intelligence emphasizes three characteristics of the thought process: (1) Its tendency to take and maintain a definite direction; (2) the capacity to make adaptations for the purpose of attaining a desired end; and (3) the power of auto-criticism.[11]

[11] See Binet and Simon: "L'intelligence des imbeciles," in _L'Annee Psychologique_ (1909), pp. 1-147. The last division of this article is devoted to a discussion of the essential nature of the higher thought processes, and is a wonderful example of that keen psychological a.n.a.lysis in which Binet was so gifted.

How these three aspects of intelligence enter into the performances with various tests of the scale is set forth from time to time in our directions for giving and interpreting the individual tests.[12] An ill.u.s.tration which may be given here is that of the "patience test," or uniting the disarranged parts of a divided rectangle. As described by Binet, this operation has the following elements: "(1) to keep in mind the end to be attained, that is to say, the figure to be formed; (2) to try different combinations under the influence of this directing idea, which guides the efforts of the subject even though he may not be conscious of the fact; and (3) to judge the combination which has been made, to compare it with the model, and to decide whether it is the correct one."

[12] See especially pages 162 and 238.

Much the same processes are called for in many other of the Binet tests, particularly those of arranging weights, rearranging dissected sentences, drawing a diamond or square from copy, finding a sentence containing three given words, counting backwards, etc.

However, an examination of the scale will show that the choice of tests was not guided entirely by any single formula as to the nature of intelligence. Binet's approach was a many-sided one. The scale includes tests of time orientation, of three or four kinds of memory, of apperception, of language comprehension, of knowledge about common objects, of free a.s.sociation, of number mastery, of constructive imagination, and of ability to compare concepts, to see contradictions, to combine fragments into a unitary whole, to comprehend abstract terms, and to meet novel situations.