There is need to understand what Intelligence is all about to psychologists. Generally speaking, the term “Intelligence” means general mental or intellectual ability, which disposese an individual to learn and positively and effectively adjust to his social environment or a part thereof. Some psychologists, going by the above understanding, refer to intelligence as the ability to comprehend and discover underlying relations between the different elements in the field of perception.
According to Prof. R.S. Woodworth, “the person who can handle novel situation in a better or efficient manner is an intelligent person;” (i.e. who can benefit from his past experiences and deal with the present situation in a better manner.)
In fact, a variety of definitions have beem given by psychologists, which can be classified into three major groups. One group of definitions places emphasis on adjustment or adaptation of the individual to his total environment or to a limited aspect of it. A sceond group places emphasis on the ability of individual to learn. The third group of definitions sees intelligence as the ability to carry on abstract thinking.
However, two definitions have been put forward which combine and cover the three views expressed by the three groups.
(1) D. Wechsler defined “Intelligence as the aggregate or global capacity of the individual to act purposefully, to think rationally and to deal effectively with his environment.
2. G.S. Stoddard says, “Intelligence is the ability to undertake activities that are characterized by:
5. Adaptiveness to a goal
6. Social Value
7. Emergence of originality and such other activities that demand a concentration of energy and resistance to emotional forces.
On the whole, intelligence is a complex function that has been defined as the ability to learn useful information and skill, adopt to new problems and conditions of life, profit from past experiences, engage in abstract and creative thinking, employ critical judgement, avoid errors, summount difficulties and exercise forsight.
Those who possess greater intelligence are quick learners, they adjust to new environment with ease and less time and they reason and argue rationally and act objectively. Hence, intelligence has been regarded as key factor to achieve success in life.
According to Charles Spearman’s theory, mental tests to establish intelligence require two types of mental ability:
1. General ability – “G” And
2. Specific ability – “S”
“G” implies the ability common to all intellectual tasks while “S” is always specific to a given task.
In the earliest days, intelligence was measured by the size of the head of the individual. This method was known as Phrenological approach. It was followed by Physiognomy, in which the shape of the face was used as the index of intelligence. This was later replaced with the use of Aesthesiometer. These methods were soon discarded because they were unscientific.
The first scientific development of intelligence was spurred on by the publications of Francis Galton, prominent among which was “English Men of Science: Their Nature and Nurture” (1874). His “Inquiries into Human Faculty”. was followed by “Natural Inheritance” (1889). Though influenced more by biological than psychological interest, Galton’s writings and statistical techniques spurred such noteworthy British psychologists as Charles Spearman to engage in the analysis of human abilities.
Galton not only stimulated investigations into individual differences, he also greatly influenced the direction of experimental efforts to measure intelligence by means of tests of imagery and sensory discrimination. He devised a test for the measurement of the delicacy of weight discrimination and invented what is today called Galton Whistle, for measuring sensitivity to high tones. He apparently assured that the simpler and measurable sensory capacities should be significantly correlated with intelligence.
However, the types of psychological testing that followed Galton’s work were objected to by Alfred Binet and his colleagues on the ground that they were too simple in nature. According to Binet and his collaborators, such simple psychological testing would contribute little to the understanding of differences in the complex and higher mental processes. This, they said is because such higher processes are where individual differences are most marked, and they are the ones that distinquish individuals most significantly and characteristically in daily activities. Whereas on the other hand, it is in the simpler sensory and motor processes that persons differ least. On above grounds, Binet and one of his collaborators, Henri, proposed to study the following functions:
Memory, the nature of mental images, imagination, attention, comprehension, suggestibility, aesthetic feelings or appreciation, moral sentiments, muscular strength and strength of will, motor skill and visual judgement.
The first attempt to develop a real psychological test on the basis of Binet’s studies in 1904 did not succeed. This first attempt was made in collaboration with Simon, for which it was called ‘The Binet-Simon scale. It was done under the auspices of a commission appointed by the then French Minister of Public Instructions, with the aim to use it to remove subnormal and mentally retarded children from the conventional schools in Paris and place them in special schools where they would learn at their own pace.
Binet successfully carried out his first test in Paris in 1905. This test was also tried in other parts of Europe by other psychologists. Consequent to the suggestions and criticisms that followed, a second and revised scale was constructed, which appeared in 1908. The revised test was also tried in other countries like Belgium, in U.S.A by Goddard, Germany by Boberitag, and in Italy by Ferrari. On account of their findings and his own investigations, Binet published another revised edition of the test in 1911. In fact, Binet is regarded as the synthesizer and originator of intelligence test. Since 1911, his scales have been revised and adopted in a number of countries for the study of individual differences in intelligence, personality, etc.
The concept of Intelligence Quotient (I.Q.) was introduced by W. Stern in 1916. It is said that intelligence grows with age up to certain level. It increases from childhood to adolescence and by the age of between 16 and 24, the maximum is reached and then remains constant.
Utility Of Intelligence Quotient Scores
1. Calculation of I.Q. score helps in diagnosing the mentally deficient and retarded persons.
2. It also helps to determine the mental level of delinquents.
3. Once the I.Q. of a person is known, it is easy to diagnose his mental disturbances and deterioration.
4. With the use of I.Q. scores, the intelligence of maladjusted children and those with specific disabilities in learning can be evaluated and they can be helped to adjust to their environment through special educational programmes.
5. Calculation of I.Q. scores also helps in educational and vocational guidance because the mental level or ability of the person can be easily determined, and on the basis of this, the person can be guided on the right vocational or career options.
6. It is also used in selection and placement of workers.