Measuring the Mind
Maurice Utrillo was a brilliant painter: his best subject at school was mathematics but he was extremely stupid in most other respects. In fact. it was only to keep her 'imbecile' child happy that his mother gave him a box of paints and canvas - these he turned into masterpieces. Was he really stupid or was he a genius? Is it possible to measure his intelligence, or, for that matter, anyone else's? The suggestion that intelligence and other human traits can be tested and indeed measured can at first sight seem very strange. The problem is solved in part by coming to understand what intelligence and other human traits are and in part by understanding what measurement is.
For example, many of the puzzles about measurement disappear if one looks at the various ways in which things can be measured. It is said that, theoretically at least. everything that exists at all exists in some amount or degree and so in principle can be measured. The practical application of this principle owes most to Sir Francis Galton; and no one has done more to devise ways in which things often thought to be unmeasurable can, in fact, be measured. On the basis of very simple procedures he established that the girls of Aberdeen were prettier than the girls of London and that some lectures to the Royal Society were measurably more boring than others. Such assertions seemed surprising only so long as all measurements were thought of as the kind used in assessing height and weight, in which certain units such as feet or pounds are counted.
But it is possible also to count the number of girls in this or that city who conform to some agreed standard of prettiness, and to count the number of fidgets in an audience at a lecture given to the Royal Society. This kind of measurement by counting is familiar in the procedures of opinion polls for the measurement of, say, the relative popularity of political leaders.
Measurement can be extended in a more interesting way in the quantitative assessment of the degrees to which variable qualities such as prettiness or likeability can be present in this or that individual. In the ordinary use of the language we distinguish individuals as extremely pretty, extremely likeable, very pretty or very likeable, pretty or likeable to an average degree and so on. The degree in which a quality is possessed can be expressed in numbers or marks out of a total such as 10 per cent or 1 00 per cent. In translating 'good' and 'very good' into 60 per cent and 90 per cent, the logic is vague and obscure but every teacher is familiar with this kind of measurement.
The assessment of human traits in numbers, marks or scores can be applied not only to physical traits such as height or weight but also to many forms of skill, athletic or industrial. A high jump is an exhibition of skill measured in feet and inches above the ground. A long jump is feet and inches along the ground. Other skills are measured by counting the number of goals scored. Industrial skills can be measured by counting the number of items produced in a given time.
In most cases the units in terms of which a trait is assessed are equal. But sometimes traits are measured in steps or stages in a series of performances which are achieved in a certain order. Levels of development are assessed in terms of the order in which a child acquires the skills of walking, talking, using a spoon, a knife and fork and so on. This is the basis of the measurement of intelligence in terms of mental age. It is possible to arrange a set of problems in order of difficulty and to divide them into sets, appropriate for children of three, for children of four, of five and so on.
A child's performance can in this way be assessed in comparison to that of a normal child of five years or one of six years, etc.
The child could then be said to have a mental age (or the intelligence of) a five-year-old or a six-year-old. The same applies to achievement in reading or in social situations, and the child can be described as having a 'reading age' of so many years, or as having reached such and such a level of 'social maturity'.
The first intelligence test of this type was drawn up in 1905 by the French psychologist Alfred Binet. It was intended to pick out children of low intelligence who would not benefit from ordinary schooling. This test was studied by an American psychologist of Stanford University, who published a revised version known as the Stanford Binet Test. This has become the standard model for most intelligence tests. It is a test for children and is graded according to age levels. The items at each age level are specially designed so that the children of that age, or older, can pass them while younger children cannot.
When a child is being tested the examiner puts increasingly difficult tests to him until he cannot answer any questions at all on a given test (this test will be called the child's 'ceiling age') and from all these results the examiner works out the child's mental age. If, for example, a child passed all tests for age four, half those for age 5 and none for age 6, his mental age would be 4t. Intelligence can be described as a ratio between mental age and chronological age. This ratio is called intelligence quotient (I.Q.). It shows how quickly a child's mental abilities are developing compared to his real age. It has the advantage of making it possible to compare the intelligence of children of different ages. For example, if two children, one aged five and one aged four, score a mental age of five on the test, then the younger child is obviously the more intelligent, and the actual difference can be worked out quite exactly.
Even a test of this kind has limitations however. It puts a heavy stress on verbal abilities, so that a child with language difficulties would be at a disadvantage. Also it indicates general mental development and does not give an adequate picture of special abilities. It is actually misleading to think of intelligence as a single ability.
Research has shown that there are various elements in intelligence. The American psychologist Thurstone, after analyzing dozens of tests performed by school children, concluded that there are seven factors in general intelligence. These are: verbal comprehension - the ability to define and understand words; word fluency - the ability to use words rapidly and coherently; number- the ability to do arithmetic; space - the ability to draw a design from memory or visualize spatial relationships; memory; perception - the ability to grasp visual details and see differences or similarities between objects; reason - the ability to find rules and principles and use them to solve or understand problems.
Thurstone observed that a child's success in one of the seven tests was related to his success in the others - but that there were interesting lapses in some cases. This suggests that intelligence is a general ability - and also a number of separate abilities.
The assessment of intelligence requires an understanding of the total system of human traits within which it occupies a distinctive place. The scientific study of intelligence is a modern development dating back only to the beginning of the present century. It was first thought of as being a physical constant like 'specific gravity', a constant characteristic of an individual, differing from one person to another, but constant for that individual throughout life. Since then it has become increasingly thought of as a biological trait which develops as do other biological traits, affected by influences of the kind which affect other biological traits.
Traits are grouped and classified in many ways. One simple division is that between observable, mainly bodily features such as being tall or short, dark or fair and traits which must be described in terms of behavior, such as being energetic or listless, sociable or reserved. The study of living things is mainly concerned with their bodily movements and actions, their habits and customs and 'ways'; in fact, with their behavior.
Anything that a living thing actually does is evidence of some ability. An ability in a very broad sense of the term is simply what a thing is able to do. There is a difference between abilities and potentialities.
An ability is something which a thing can do. In contrast, potentiality, or aptitude, is something which it could do under special conditions. A child has linguistic ability if he shows an actual mastery of a foreign language. He has linguistic aptitude if he could develop mastery of one or more foreign languages, even if he actually has no marked ability in any foreign language.
One can say that a boy has the potentiality of being a distinguished cricketer even though he has never played the game. We like to believe that there are many 'mute inglorious Miltons' among those who lack training or encouragement to use poetic language. Some would say that there are none; that 'Genius will out'; that if the potential of poetic genius is there it cannot fail to find expression. On the other hand there is a widely accepted philosophy of education which believes that it is precisely the aim of education to bring out potentialities, to turn aptitudes into abilities.
Aptitudes are more difficult to detect and assess than abilities. The existence of a man's ability to do something is sufficiently proved by the fact that he actually does it. The degree of his ability is sufficiently measured by his record, usually his best record - as for example in a high jump or a long-jump. His intelligence is conveniently assessed by his performance in a set of scholastic tests or a similar record of performances in some other set of examinations or tests.
Aptitude, on the other hand, can often be reasonably suspected when it cannot be proved or measured by actual performance.
Some test performances can suggest the presence of aptitude. But there are many ways in which potential ability can be prevented from finding expression and many good grounds on which high potentiality can be only suspected.
Abilities should also be distinguished from tendencies, inclinations, bents or biases. These can be described in various ways. To say that a child has arithmetical or musical ability is to say only that he can do sums or can perform in musical ways.
To say that he likes or has a bent for arithmetic or music implies that he shows more enthusiasm for arithmetical or musical pursuits than is common. Inclinations are contrasted with disinclinations.
Ability or lack of ability can be combined with inclination or disinclination in important ways.
In the broadest sense in which the term 'ability', 'potentiality' and 'tendency' have been so far used these terms are not distinctively psychological or even biological concepts. They are logical concepts, applied not within the confines of this or that special science, but in a more general sense. In this more general sense it can be said that a car, for example, is fast- has the ability to go quickly - that it has the potentiality of a racer, that it tends to stall.
In contrast with these highly general uses of such terms as ability, potentiality and tendency, there are narrower uses of these trait-terms which are distinctive of psychology and related biological sciences.
In the more restricted usage we do not say that a living thing has the ability to do anything which it does and cannot help doing, as a bird builds nests or a spider constructs webs. We say that a living thing has an ability only when it does something which at first it cannot do and later can do, or which it at first does only with difficulty but later with ease, which can therefore be reckoned an achievement. Such actions are also generally a source of satisfaction to those who perform them and are acclaimed as achievements by others.
A child almost from birth can cough or sneeze and obtain food from it's mother's breast - as a bird can build a nest or a spider can construct a web. These are wonderful things to do but they are not achievements; nor in the strictest sense are they expressions of ability. Later the child learns to blow his nose, dress himself and tie up his shoe laces. These are abilities.
And so step by step the child passes through successive levels of achievements to performance in terms of which intelligence, athletic and other high abilities and skills are defined.
This narrower use of terms such as ability is that which is of chief interest to parents, teachers and to students of psychology. It can accordingly be described as the distinctively psychological uses of trait-terms.
The study of traits in the psychological sense is complicated by a pervasive ambiguity. It arises from the distinction between the manner in which the trait is expressed, and the underlying elements of the make-up of the individual as a result of which the trait in question is possessed.
Thus a distinction must be drawn between athletic ability as directly expressed in performance in, say, cricket as measured by scores in batting or bowling, and the features in the make-up of the athlete (his 'eye', his reaction-time, his physical strength) as a result of which he shows his skill in cricket.
So too with intelligence. A distinction is drawn between the sort of performance in which intelligence is displayed and the elements in the make-up of an individual by virtue of which intelligence can be displayed.
Thus if the view is taken that intelligence is best displayed in all-round scholastic ability, it may be further suggested that this all-round competence is displayed as a result of a certain biological trait or element in the individual constitution, consisting of the ease or rapidity with which connections or associations are formed in the nervous system.
The distinction between the activity in which intelligence or other traits is directly expressed and the underlying constitutional element by virtue of which intelligence or other traits can be explained, arises in all the queries which can be raised concerning intelligence and other traits.
To take intelligence for example, the queries are of the following kind: Is it innate or acquired? Is it a general or a specific trait? Is it the same thing in everyone or are there various kinds of intelligence?
Is it essentially a cognitive ability, partly a social skill or a personality trait?
There is fairly general agreement that intelligence is displayed in all-round general ability and is largely constant and inborn. But no ability is entirely general.
There must be various kinds of general ability, various kinds of intelligence according to whether the battery of tests or table of scores are a set of scholastic tests, or a set of tests of verbal skills, practical skills or other kinds of performance.
Psychologists therefore divide intelligence into verbal intelligence, practical intelligence and sometimes social intelligence.
So it is in deciding whether intelligence is innate or acquired. There is evidence against the view that any ability is entirely innate or entirely acquired, but every known ability seems to have some inborn or constitutional basis and every known ability is to some extent subject to improvement by training or experience.
Recently there has been a movement away from the original rigid account of intelligence to one that is more flexible, more liberal, more human and more in accordance with the institutions of the understanding parent and the experienced teacher.
The initial orthodox 'scientific' doctrine was that the trait described as intelligence was a simple, constant quality like a physical characteristic such as 'specific gravity' defining an inborn endowment of all-round general cognitive ability. Intelligence was believed to differ from one individual to another, and also to distinguish between social, national and other 'cultural' groups.
The contemporary view differs not so much on one fundamental point as on a number of points which add up to a fundamental difference. Intelligence is still considered to be an all-round general ability largely inherited. But it is now seen as something more variable and more complex, incorporating traits hitherto distinguished from purely cognitive abilities such as features of motivation and personality.
Today intelligence is not regarded as a simple and single trait. It is thought of as a variety of traits in which one can distinguish a number of kinds of intelligence, such as verbal, practical and social intelligence, and such differences as those between urban and country communities, lower animals and human beings and between nations and other cultural groups.
No ability and no trait is now regarded as entirely inborn or entirely acquired. All traits probably have an innate basis, but all traits can be developed or otherwise modified by training, education or other environmental influences.
Intelligence in all its forms can be viewed as an expression of personality as a whole. The idea of personality incorporates the idea of 'individuality'. Each individual is unique, that is, different from every other person. Individuality is shown in simple bodily traits, and perhaps even more in the exercise of intelligence, in style of thought, language and other skills.
We are only beginning to recognize the number of ways in which the intelligence of an individual is expressed and may be modified by the influences of education, culture and other social forces.