IQ TEST

The first attempts at measuring human intelligence were taken as early as XIX century. This was when psychologists first came to consider if intelligence is linked with brain mass, stature, or other physical attributes. The first tests, however, did not measure the intellect as we define it today, but rather general knowledge and mathematical skills. That’s because they consisted of tasks similar to those used in schools.

The French psychologist Alfred Binet was a person who had an immense influence on our knowledge of how the human mind works. In the year 1905, together with his co-worker, doctor Teodor Simon, he worked out the problems for the first real IQ test ever. Those tasks were intended to check if the examined child is making intellectual progress. The result was not given as an intelligence quotient, like in modern tests, but rather as a so called mental age. Mental age, a concept introduced to the world of science by Alfred Binet, was the level of the child’s intellectual advancement. The mental age could be completely different from his metrical age. A lower result meant mental retardation; a higher result meant above average mental capabilities. If the metrical age and mental age were equal, it would mean that the child is making normal progress.

Another person responsible for very important changes in the science of human mind was an American scientist, David Wechsler. Until thirties, IQ tests were never used to measure mental capabilities of adults, because the concept of mental age was only meant for children. David Wechsler made radically different assumptions when devising his own test. He assumed that the intelligence distribution in a population has the attributes of normal (Gaussian) distribution. In a given society, people of average intelligence are a majority; as for people with exceptionally high or low intelligence, the higher their deviation from the average level is, the less common they are. 100 IQ was picked as the average result. Most people get results that deviate from the average by no more than 15 points. A result higher than 115 is above average; a result higher than 130 is exceptionally high.