Psychological testing is one of the
newest disciplines of one of the youngest sciences Psychology. It is
essentially an objective and standardized measure of a sample of behavior. Its
principal function is to measure differences between individuals or the
reactions of the same individual in different situations. Initially, it was
employed to identify different grades of feeble-mindedness. With time, its application
has grown to cover a wide range of activities, including the examination of
emotionally maladjusted, delinquents, and other subnormal deviates. In India
today, schools are its major users. They employ psychological testing to classify
children between intellectually retarded and the gifted and for educational and
vocational counseling. Employers use it in the selection of their key staff, in
addition to normal interviewing.
ORIGIN OF PSYCHOLOGICAL TESTING
The science of psychological
testing developed with the growing concern for the care of the mentally
handicapped, who was the victim of neglect, ridicule, and even torture, in the
19th century. With the establishment of various institutions for the mentally
retarded across Europe and the United States at that time, an objective system of
classification between the insane and the feebleminded was necessitated for
admission to these institutions. The insane were characterized by emotional disorders
which might or might not be accompanied by intellectual deterioration from an
initially normal level, while the feebleminded were identified by intellectual
defects, present from birth or early infancy. Probably the first statement of
this distinction is found in a two-volume work by the French physician, Esquire,
who had devoted over 100 pages to feeblemindedness in 1838. Based on his
subject's use of language, Esquire, distinguished between two grades of imbecility
and three grades of idiocy. At around the same time, another French physician,
Seguin, pioneered the training of the feebleminded. He rejected the notion that
mental deficiency was incurable.
However, the focus of most
experimental psychologists at that time was on the formulation of a generalized
description of human behavior, rather than the measurement of individual
differences. It was the British biologist, Sir Francis Galton, who was
instrumental in launching the testing movement on its course. In 1882, he
established an anthropometric laboratory in South Kensington Museum, London,
where he measured certain physical traits of individuals such as keenness of
vision and hearing, muscular strength, reaction time, and other simple sensorimotor
-functions for a small fee. He devised several simple tests, such as
"Gabon bar" and "Gabon whistle", to administer these tests.
Gabon believed that tests of sensorimotor discrimination could serve as a means
of gauging a person's intellect. Galton also pioneered the application of
rating scales and questionnaire methods, as well as the use of the "free
association" technique, subsequently employed for various purposes. He
also developed statistical methods for the analysis of data on individual
differences.
EARLY MENTAL TESTS
Galton's work received a further
boost when an American psychologist, James McKeen Cattell, developed what he
called "mental tests" - a term used for the first time in the
psychological literature - in 1890. Cattell's tests, administered annually to
college students to determine their intellectual level, were carried out individually
and included measures of muscular strength, speed of movement, sensitivity to
pain, keenness of vision and hearing, weight discrimination, reaction time, and
memory. Like Galton, Cattell believed that a measure of intellectual functions
could be obtained through the tests of sensory discrimination and reaction
time.
Several other tests, devised by
European psychologists of that period, tended to cover somewhat more complex
functions. Kraepelin, for example, devised a long series of tests to measure
practice effects, memory, and susceptibility to fatigue and distraction. He was
more interested in the clinical examination of psychiatric patients. French
psychologists, Binet and Henri, formulated a long list of tests of memory,
imagination, attention, comprehension, suggestibility, aesthetic appreciation,
and many other functions that eventually led to the development of the renowned
Binet-Simon "intelligence scales".
THE RISE OF
INTELLIGENCE TESTS
The Binet-Simon scale, also known
as the 1905 Scale, was made up of 30 problems arranged in ascending order of
difficulty. The difficulty level was set empirically by administering the tests
to 50 normal children, aged 3 to 11 years, and some retarded and feebleminded
children. The tests were designed to cover a wide variety of functions, with
special emphasis on judgment, comprehension, and reasoning, which Binet
regarded as essential components of intelligence. In 1908, Binet increased the
number of tests and grouped them into age levels, and called them tests for
determining the "mental age", - 1. e. the age of a normal child whose
performance he equaled. In 1911, some more tests were added for ages over 11
years and the scale was extended to the adult level.
GROUP TESTING
However, the Binet tests are individual
scales, as they are administered to only one person at a time. Many of the
tests in these scales simply require oral responses from the subject or
necessitate the manipulation of materials. Such tests are essentially clinical
instruments, suited to an intensive study of individual cases. It was only
after the United States entered World War I in 1917 that a group of American
army psychologists developed what has come to be known as Army Alpha and Army
Beta tests to determine the general intellectual level of large groups. Such
information was needed to facilitate administrative decisions, like rejection
or discharge from military service, assignment to different types of services,
or admission to officer teaming camps. At the end of the war, the army tests
were released for civilian use - a measure that spurred the growth of the large-scale
testing programs by leaps and bounds. Soon schools were using them to assess the.
general intelligence level, or what is commonly known as "IQ"
(intelligence quotient) of their pupils.
SPECIAL APTITUDE TESTS
But gradually it became apparent
that intelligence tests were limited in their coverage, as they primarily
measured verbal ability and, to some extent, the ability to handle numerical
and other symbolic relations. Many psychologists came to realize the term
"intelligence test" was a misnomer since it represented only certain
aspects of intelligence. This led to the rise of special aptitude tests, such
as mechanical, clerical, musical, and artistic abilities of the subjects, in
addition to his intellectual ability.
MEASUREMENT OF PERSONALITY
Still, all these tests failed to
measure the overall personality of an individual Efforts were, therefore,
directed towards non-intellectual aspects of behavior, and tests designed for
this purpose are commonly known as "personality tests", covering such
characteristics as emotional adjustment, social relations, motivation, interests,
and attitudes.
An early precursor of personality
testing may be recognized in Kraepelin's use of the free association tests with
abnormal patients. Sommer (1894) also suggested that the free association test
might be used to differentiate between the various forms of mental disorders.
Although originally devised for other purposes, these procedures were
eventually employed by many psychologists in constructing some most common
types of personality tests. The prototype of the personality questionnaire, or self-report
inventory, is the personal data sheet developed by Woodworth during World War
I. This test was designed as a rough screening device for identifying seriously
neurotic men who would be unfit for military service. In the questionnaire, an
attempt was made to subdivide emotional adjustment inventories into more
specific forms, such as home adjustment, school adjustment, and vocational
adjustment.
Another approach to the measurement
of personality is through the application of performance or situational
tests. In such tests, the subject has a task to perform whose purpose is
generally disguised. Most of these tests simulate everyday life situations
quite closely. The first extensive application of such techniques is to be found
in the tests developed in the late twenties and early thirties by Hart’s home, May, and their associates (1928-1930). This series, standardized on school children,
was concerned with such behavior as cheating, lying, stealing, cooperativeness, and persistence. During World War II, the Assessment Program of the Office of Strategic
Service (OSS, 1948) conducted these tests on adults. These tests were concerned
with relatively complex and subtle social and emotional behavior and required
rather elaborate facilities and trained personnel for administration. The interpretation
of the subject's responses was also rather subjective.
A third approach to the study of
personality and which has grown phenomenally, especially among clinicians, is the
Projective technique. In such tests, the subject is given a relatively
unstructured task that permits wide latitude in its solution. The assumption
underlying such methods is that the individual will project his characteristic
modes of response into such a task. The& projective technique is
also more or less disguised in its purpose, like performance and situational
tests.
However, all types of personality
tests present difficulties, both practical and theoretical. The construction
and use of personality inventories are beset with special difficulties over and
above the common problems encountered in psychological testing. The question of
faking and malingering is far more acute in personality measurement than in
aptitude testing. Yet, there is a silver lining beyond the cloud: the research
on the measurement of personality has reached impressive proportions since 1950
and many ingenious devices and technical improvements are under investigation.
TEST RELIABILITY
Psychologists have attempted to
develop various methods of determining the reliability of tests. Test
reliability indicates the extent to which individual differences in test scores
are attributable to chance errors of measurement and the extent to which they
are attributable to the true differences in the characteristic under
consideration. In more technical terms, every measure of test reliability denotes
what proportion of the total variance of test scores is error variance. An obvious source of error variance
is the random fluctuation of performance occurring from one session to another.
This may result from uncontrolled testing conditions, such as extreme changes
in weather, sudden noises, and other distractions. This may also arise from the
subject's illness, fatigue, emotional strain, or anxiety. This type of error
variance is attributed to what is known in psychological parlance as "Temporal
stability".
Another problem is presented by the
greater situational specificity of responses in the sphere of personality. E.g.,
an individual might be quite sociable and extroverted at the office, but
elsewhere not. Such specificity in turn relates to the difficulty of grouping
items into clearly defined categories of personality traits.
First, personality inventories may
be recognized as intrinsically crude instruments and their application
restricted accordingly. Most psychologists today would probably accept some
combination of the two approaches, although a few may align themselves exclusively
behind one or the other. Personality inventories may also be evaluated at a
more basic level, in terms of their theoretical assumptions and underlying
rationale. The first concern is the type of information that the personality
inventories are designed to elicit. The second pertains to the inherent ambiguity
of inventory responses. Because the early personality inventories were designed
as a rapid substitute for the psychiatric interview, it is frequently assumed that
the response to each symptom or die other behavior characteristics described by
the question. From another angle, personality inventories have been attacked because
their responses are necessarily ambiguous.
In interpreting test scores,
personality and aptitudes cannot be kept apart. An individual's performance on
an aptitude test, as well as his performance in school, on the job, or in any
other context, is influenced by his achievement drive, his persistence, his
value system, his freedom from handicapping emotional problems, and every other
characteristic traditionally classified under the heading of "personality".
Even more important is the cumulative effect of personality characteristics on
the direction mid extent of the individual's intellectual development. The
relationship between personality and intellect is reciprocal. Not only do
personality characteristics affect intellectual development, but intellectual level
also affects personality development. The success the individual attains in the
development and use of his aptitudes is bound to influence his emotional adjustment,
interpersonal relations and self-concept. In the self-concept, we can see most
clearly the mutual influence of aptitudes and personality.
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