History of the IQ test

IQ tests are by far the most popular tests in psychology. But few people know how they appeared and when they were developed. Since we offer an official IQ test, we felt it appropriate to collect the most up-to-date data on the history of the IQ test and its evolution.

The problem of assessing intelligence

William Stern is the man who coined the abbreviation for IQ (Intelligenz-Quotient), which we know as an assessment of intellectual ability in our speech today.

Interest in assessing human capabilities in the field of intelligence was manifested thousands of years ago, but the first steps towards its measurement were taken relatively recently.

In 1904, at the request of the French government, psychologist Alfred Binet and his colleague Theodore Simon tried to develop a system which could identify students who would experience difficulties in their studies. They developed and administered tests which helped them identify groups of people who performed more or less successfully. So the Binet-Simon tests and their rating scale were the first standardized IQ tests.

In 1916, psychologist Lewis Terman adapted the French scale to fit the American education system. His scale became the standard for measuring intelligence in the United States for several decades.

It should be noted that the IQ level measurement was calculated as mental age divided by chronological age and then multiplied by 100. For example, if the mental age of a child was 14.5 years old, and his chronological age was 11 years old, then IQ was calculated as follows:
14.5 / 11 * 100 = 131.8
Such a test was only for pupils and children.

First adult IQ test

After this, IQ testing maintained its usefulness during the First World War, and also became used to determine the intelligence level of immigrants who tried to cross the US borders.

The first breakthrough in the field of intelligence testing was achieved with the publication of the Robert Wexler scale. Wexler's testing was based on a comparison of test results between individuals of the same age group.

Subsequently, psychologists tried to develop IQ tests that included questions to assess not only mathematical or verbal skills but also the ability to classify and solve logical and spatial problems and determine the capabilities of a person’s memory.