Intelligence Testing throughout the Years
If people today wanted to know how intelligent they are, all they have to do is take an intelligence test and they’ll immediately know their intelligence quotient or IQ, which is a numerical assessment of their mental capability. Essentially, this number is the ratio of their mental age to their chronological age, and it gives people an idea of how they rank against the rest of the population in terms of standard intelligence.
However, these intelligence tests became available only in the last century. Prior to that, people didn’t really have a way of measuring intelligence and they relied only on empirical methods, which were hardly capable of producing accurate results.
The first formal intelligence test was created in the early part of the 20th century by French psychologist Alfred Binet, with the help of his colleague Theodore Simon. It was developed so that children can be classified into different classes to facilitate effective school education in France. More specifically, these tests were used to identify which children needed special assistance or had to be placed in special classes.
This first IQ test is known today as the Binet-Simon intelligence test, and is still used as the basis of modern IQ tests these days. But even Binet himself admits that there are several limitations to their test, primarily because intelligence is too broad a concept to be quantified using just a series of questions. It is for this reason that the original test had had to undergo several revisions over the years following its initial use.
In 1916, the test was introduced in the United States by Stanford University psychologist Lewis Terman, who modified it after conducting a series of studies involving randomly chosen American adult participants. The published version of this new test, known as the Stanford-Binet intelligence test, has become the standard IQ test used in the US to this day.
Still, many experts were not confident of the precision of these IQ tests, maintaining like Binet did that there are so many other areas of intelligence that these tests did not take into consideration. One of these skeptics is American psychologist David Wechsler. He went into an in-depth study of human intelligence and in 1955, came up with his own version of the IQ test, which is now known by the name of WAIS or Wechsler Adult Intelligence Scale.
The WAIS consists of 14 subtests and scores a tester on two different scales. There are three separate scores that you can get from a WAIS intelligence test: a verbal score, a composite score and a performance score. The unique scoring system used in the WAIS tests made it possible to identify learning disabilities, as well as potential for giftedness in both adults and children.
Today, most standard IQ tests are still patterned after the Stanford-Binet test, although the scoring system follows the one designed by Wechsler. In this system, an individual’s score is acquired by comparing his test results with the average score of his age group. Based on this scoring method, approximately 60% of the population has an IQ score between 85 and 115, with 100 being the median score.