CONCEPT OF MENTAL AGE AND
INTELLIGENCE QUOTIENT
Mental Age (MA)
The
term mental age refers to the level of native mental ability of an individual
in relation to the chronological age of the average individual at this level. The
concept of mental age was introduced by French Psychologist, Alfred Binet: and
it is determined by the performance of the individual on a standard
intelligence test. The mental age (MA) is a device for comparing the scores
made by an individual on a given test with the scores made by many other
individuals on the same test. It is based on the principle of the normal
distribution of intelligence that the majority of individuals of a
particular age are of normal intelligence and that they have a mental level
approximating that age, which could be termed as their mental age. Suppose the mean
score obtained on the intelligence test by 10 year old children is 48, then any
individual who earns a score of48, regardless of his chronological performance
compared to the performance of the majority of the individual of his age, he is
said to be a higher mental age.
Intelligence Quotient (IQ)
An
individual’s level of intelligence is usually expressed in quantitative terms
as a ratio between his mental age and chronological age. This ratio is known as
intelligence quotient or IQ. The concept of IQ was formulated by William
Stern, a German Psychologist, in 1912. IQ is the quotient of mental age
(MA) divided by the chronological age (CA) usually expressed as a multiple of
100 to avoid fractions. The formula for intelligence quotient is
IQ=
MA/CA*100
[MA- Mental age, CA- Chronological Age]
IQ is a
device to express the exact relationship between the chronological age and mental
age of the individual. It is an expression of relative performance at different
ages. An individual’s IQ scores, ignoring errors of measurements, remains the same
from one age to all others unless there is a change in ability level
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