Part 2 (1/2)
That the industrially inefficient are often of subnormal intelligence has already been demonstrated in a number of psychological investigations. Of 150 ”hoboes” tested under the direction of the writer by Mr. Knollin, at least 15 per cent belonged to the moron grade of mental deficiency, and almost as many more were border-line cases. To be sure, a large proportion were found perfectly normal, and a few even decidedly superior in mental ability, but the ratio of mental deficiency was ten or fifteen times as high as that holding for the general population. Several had as low as 9- or 10-year intelligence, and one had a mental level of 7 years. The industrial history of such subjects, as given by themselves, was always about what the mental level would lead us to expect--unskilled work, lack of interest in accomplishment, frequent discharge from jobs, discouragement, and finally the ”road.”
The above findings have been fully paralleled by Mr. Glenn Johnson and Professor Eleanor Rowland, of Reed College, who tested 108 unemployed charity cases in Portland, Oregon. Both of these investigators made use of the Stanford revision of the Binet scale, which is especially serviceable in distinguis.h.i.+ng the upper-grade defectives from normals.
It hardly needs to be emphasized that when charity organizations help the feeble-minded to float along in the social and industrial world, and to produce and rear children after their kind, a doubtful service is rendered. A little psychological research would aid the united charities of any city to direct their expenditures into more profitable channels than would otherwise be possible.
OTHER USES OF INTELLIGENCE TESTS. Another important use of intelligence tests is in the study of the factors which influence mental development.
It is desirable that we should be able to guard the child against influences which affect mental development unfavorably; but as long as these influences have not been sifted, weighed, and measured, we have nothing but conjecture on which to base our efforts in this direction.
When we search the literature of child hygiene for reliable evidence as to the injurious effects upon mental ability of malnutrition, decayed teeth, obstructed breathing, reduced sleep, bad ventilation, insufficient exercise, etc., we are met by endless a.s.sertion painfully unsupported by demonstrated fact. We have, indeed, very little exact knowledge regarding the mental effects of any of the factors just mentioned. When standardized mental tests have come into more general use, such influences will be easy to detect wherever they are really present.
Again, the most important question of heredity is that regarding the inheritance of intelligence; but this is a problem which cannot be attacked at all without some accurate means of identifying the thing which is the object of study. Without the use of scales for measuring intelligence we can give no better answer as to the essential difference between a genius and a fool than is to be found in legend and fiction.
Applying this to school children, it means that without such tests we cannot know to what extent a child's mental performances are determined by environment and to what extent by heredity. Is the place of the so-called lower cla.s.ses in the social and industrial scale the result of their inferior native endowment, or is their apparent inferiority merely a result of their inferior home and school training? Is genius more common among children of the educated cla.s.ses than among the children of the ignorant and poor? Are the inferior races really inferior, or are they merely unfortunate in their lack of opportunity to learn?
Only intelligence tests can answer these questions and grade the raw material with which education works. Without them we can never distinguish the results of our educational efforts with a given child from the influence of the child's original endowment. Such tests would have told us, for example, whether the much-discussed ”wonder children,”
such as the Sidis and Wiener boys and the Stoner girl, owe their precocious intellectual prowess to superior training (as their parents believe) or to superior native ability. The supposed effects upon mental development of new methods of mind training, which are exploited so confidently from time to time (e.g., the Montessori method and the various systems of sensory and motor training for the feeble-minded), will have to be checked up by the same kind of scientific measurement.
In all these fields intelligence tests are certain to play an ever-increasing role. With the exception of moral character there is nothing as significant for a child's future as his grade of intelligence. Even health itself is likely to have less influence in determining success in life. Although strength and swiftness have always had great survival value among the lower animals, these characteristics have long since lost their supremacy in man's struggle for existence.
For us the rule of brawn has been broken, and intelligence has become the decisive factor in success. Schools, railroads, factories, and the largest commercial concerns may be successfully managed by persons who are physically weak or even sickly. One who has intelligence constantly measures opportunities against his own strength or weakness and adjusts himself to conditions by following those leads which promise most toward the realization of his individual possibilities.
All cla.s.ses of intellects, the weakest as well as the strongest, will profit by the application of their talents to tasks which are consonant with their ability. When we have learned the lessons which intelligence tests have to teach, we shall no longer blame mentally defective workmen for their industrial inefficiency, punish weak-minded children because of their inability to learn, or imprison and hang mentally defective criminals because they lacked the intelligence to appreciate the ordinary codes of social conduct.
CHAPTER II
SOURCES OF ERROR IN JUDGING INTELLIGENCE
ARE INTELLIGENCE TESTS SUPERFLUOUS? Binet tells us that he often encountered the criticism that intelligence tests are superfluous, and that in going to so much trouble to devise his measuring scale he was forcing an open door. Those who made this criticism believed that the observant teacher or parent is able to make an offhand estimate of a child's intelligence which is accurate enough. ”It is a stupid teacher,”
said one, ”who needs a psychologist to tell her which pupils are not intelligent.” Every one who uses intelligence tests meets this att.i.tude from time to time.
This should not be surprising or discouraging. It is only natural that those who are unfamiliar with the methods of psychology should occasionally question their validity or worth, just as there are many excellent people who do not ”believe in” vaccination against typhoid and small pox, operations for appendicitis, etc.
There is an additional reason why the applications of psychology have to overcome a good deal of conservatism and skepticism; namely, the fact that every one, whether psychologically trained or not, acquires in the ordinary experiences of life a certain degree of expertness in the observation and interpretation of mental traits. The possession of this little fund of practical working knowledge makes most people slow to admit any one's claim to greater expertness. When the astronomer tells us the distance to Jupiter, we accept his statement, because we recognize that our ordinary experience affords no basis for judgment about such matters. But every one acquires more or less facility in distinguis.h.i.+ng the coa.r.s.er differences among people in intelligence, and this half-knowledge naturally generates a certain amount of resistance to the more refined method of tests.
It should be evident, however, that we need more than the ability merely to distinguish a genius from a simpleton, just as a physician needs something more than the ability to distinguish an athlete from a man dying of consumption. It is necessary to have a definite and accurate diagnosis, one which will differentiate more finely the many degrees and qualities of intelligence. Just as in the case of physical illness, we need to know not merely that the patient is sick, but also why he is sick, what organs are involved, what course the illness will run, and what physical work the patient can safely undertake, so in the case of a r.e.t.a.r.ded child, we need to know the exact degree of intellectual deficiency, what mental functions are chiefly concerned in the defect, whether the deficiency is due to innate endowment, to physical illness, or to faults of education, and what lines of mental activity the child will be able to pursue with reasonable hope of success. In the diagnosis of a case of malnutrition, the up-to-date physician does not depend upon general symptoms, but instead makes a blood test to determine the exact number of red corpuscles per cubic millimeter of blood and the exact percentage of haemoglobin. He has learned that external appearances are often misleading. Similarly, every psychologist who is experienced in the mental examination of school children knows that his own or the teacher's estimate of a child's intelligence is subject to grave and frequent error.
THE NECESSITY OF STANDARDS. In the first place, in order to judge an individual's intelligence it is necessary to have in mind some standard as to what const.i.tutes normal intelligence. This the ordinary parent or teacher does not have. In the case of school children, for example, each pupil is judged with reference to the average intelligence of the cla.s.s. But the teacher has no means of knowing whether the average for her cla.s.s is above, equal to, or below that for children in general. Her standard may be too high, too low, vague, mechanical, or fragmentary.
The same, of course, holds in the case of parents or any one else attempting to estimate intelligence on the basis of common observation.
THE INTELLIGENCE OF r.e.t.a.r.dED CHILDREN USUALLY OVERESTIMATED. One of the most common errors made by the teacher is to overestimate the intelligence of the over-age pupil. This is because she fails to take account of age differences and estimates intelligence on the basis of the child's school performance in the grade where he happens to be located. She tends to overlook the fact that quality of school work is no index of intelligence unless age is taken into account. The question should be, not, ”Is this child doing his school work well?” but rather, ”In what school grade should a child of this age be able to do satisfactory work?” A high-grade imbecile may do average work in the first grade, and a high-grade moron average work in the third or fourth grade, provided only they are sufficiently over-age for the grade in question.
Our experience in testing children for segregation in special cla.s.ses has time and again brought this fallacy of teachers to our attention. We have often found one or more feeble-minded children in a cla.s.s after the teacher had confidently a.s.serted that there was not a single exceptionally dull child present. In every case where there has been opportunity to follow the later school progress of such a child the validity of the intelligence test has been fully confirmed.
The following are typical examples of the neglect of teachers to take the age factor into account when estimating the intelligence of the over-age child:--
_A. R. Girl, age 11; in low second grade._ She was able to do the work of this grade, not well, but pa.s.sably. The teacher's judgment as to this child's intelligence was ”dull but not defective.” What the teacher overlooked was the fact that she had judged the child by a 7-year standard, and that, instead of only being able to do the work of the second grade indifferently, a child of this age should have been equal to the work of the fifth grade. In reality, A. R. is definitely feeble-minded. Although she is from a home of average culture, is 11 years old, and has attended school five years, she has barely the intelligence of the average child of six years.
_D. C. Boy, age 17; in fifth grade._ His teacher knew that he was dull, but had not thought of him as belonging to the cla.s.s of feeble-minded. She had judged this boy by the 11-year standard and had perhaps been further misled by his normal appearance and exceptionally satisfactory behavior. The Binet test quickly showed that he had a mental level of approximately 9 years. There is little probability that his comprehension will ever surpa.s.s that of the average 10-year-old.