For centuries, people have been interested in knowing the level of their intelligence. Many scientists have thought about creating methods for measuring the quality of the mind. Paul Broca and Sir Francis Galton in the 19th century proposed a theory for determining the quality of intelligence from the size of the skull. The larger the skull, they believed, the smarter the person is.
At the same time, Wilhelm Wundt offered his version. He put forward the idea of defining IQ by a person’s ability to analyze his own thoughts.
The theories of these scientists are considered outdated and are not used to measure human intelligence. But these were the first attempts to create ways to measure intelligence and formed the basis for creating a more accurate IQ https://iq-test-international.org/eng_test.
The first real IQ test
The first IQ test appeared in 1904. It was developed by the Frenchmen Alfred Binet and Théodore Simon. Scientists did not think about creating something universal. Everything happened by chance. The country’s Ministry of Education asked scientists to create a tool to distinguish lazy but intelligent children from intellectually retarded ones.
Alfred Binet was a lawyer, but became very interested in psychology. For the sake of science, the scientist left law. Developing the test, Binet and Simon operated with attention, memory, and problem-solving skills.
The first IQ test included 30 questions. In the tasks, it was necessary to distinguish boredom from fatigue. The test taker was asked to follow a moving object with one eye.
The test quickly gained popularity. It began to be used outside of France. So the first IQ test, called the Binet-Simon scale, was born.
Scientists understood that the test is limited and does not take into account:
external factors affecting the level of intelligence.
Binet believed that intelligence is too complex to be measured by numbers alone.
How is IQ measured today
Stanford University scientist Lewis Terman adapted the French test for the English-speaking consumer by adding another measurement scale. It is now called the Stanford-Binet test and is widely used. Over time, changes were made to it.
In 1917, American scientist Robert Yerkes developed Alpha and Beta tests for the Army to determine the ability of recruits to hold leadership positions. The tests were also used in other areas of life.
American psychologist David Wexler decided to rid the tests of the shortcomings of the Stanford-Binet scale. The scientist created 3 IQ tests:
WAIS – test for adults;
WISC – test for schoolchildren;
WPPSI − test for preschoolers and elementary school.
The IQ test for adults evaluates a person’s intelligence compared to other people in the same age category. It is now called WAIS-IV and is widely used.