Intelligence quotient (IQ) testing is a method used to assess human intelligence. The tests are designed to measure a range of cognitive abilities and skills, providing a numerical value that is used as a standard measure of an individual’s mental agility and capacity. The first Intelligence Quotient (IQ) test was created in 1905 and was designed to measure the intelligence a child needs to succeed in an academic environment. It covers language, information/knowledge, memory, math, spatial, thinking (cognitive ability, speed/ response time) and fine motor skills.
By age 5, most children in America will have been given some kind of intelligence test– for private school admissions, gifted and talented qualification or public school placement in slow, average or accelerated learning groups.
The two most commonly given IQ tests are the Stanford-Binet (SB5) and the Weschler Preschool and Primary Scale of Intelligence-III (WPPSI). The Stanford-Binet can be administered to children aged two and up, and the WPPSI can be given to children ages two through seven. Questions on these IQ tests and the IQ Score Ranges do not change from year to year. In fact, the Stanford-Binet has only been changed five times since 1905, and the WPPSI has changed a mere two times since 1967.
History of IQ Testing
The concept of measuring intelligence dates back to the late 19th and early 20th centuries. The first precursor to modern IQ tests was developed by the British scientist Sir Francis Galton, who was interested in measuring intelligence based on sensory acuity and reaction times. However, his methods were later found to have little correlation with other measures of intelligence.
The term “intelligence quotient,” or “IQ,” was first coined by the German psychologist William Stern in the early 20th century. The concept was further developed by Alfred Binet and Theodore Simon in France in 1905. They created the Binet-Simon Test to measure children’s intelligence to identify those who might require additional educational assistance. This test, designed to evaluate a child’s mental age, became the foundation for modern IQ testing.
In 1916, Lewis Terman of Stanford University revised the Binet-Simon scale and published it as the Stanford-Binet Intelligence Scales. This is considered the first official IQ test, providing a numerical score that could be compared across age groups.
Early Uses of IQ Testing
Early IQ tests were primarily used in educational settings. Binet intended his test to identify children in need of extra help, believing that education and environment played significant roles in intellectual development. However, the test was often used to place children into different educational tracks based on their scores, and it wasn’t always used in the way Binet intended.
In the early 20th century, IQ tests were adopted by the U.S. Army during World War I to select the best candidates for officer training. They also played a significant role in the immigration policy of the United States during the 1920s, as officials used them to assess the ‘fitness’ of immigrants— a use that was controversial and ultimately led to many discriminatory practices.
In the later part of the 20th century, the use of IQ tests broadened. They were used in clinical settings for diagnosing intellectual disabilities, and in workplaces for employee selection and evaluation. They also began to play a role in legal settings, sometimes being used to assess competency in criminal cases.
It’s important to note that while IQ tests can provide some insights into an individual’s cognitive abilities, they do not capture the full range of human intelligence and they certainly don’t determine a person’s worth or potential. The value of an IQ score is limited, and it is only one of many measures of cognitive ability.
IQ Score Ranges
Intelligence Quotient (IQ) scores are typically divided into different ranges that classify an individual’s cognitive ability. Here are some commonly used categories based on the standard scoring scale, where the average score is set at 100:
- Below 70 – Extremely Low/Intellectual Disability: An IQ score below 70 typically indicates significant cognitive impairments. This is usually classified as an intellectual disability. Individuals in this range may require more extensive support for daily activities.
- 70-79 – Borderline Intellectual Functioning: Individuals with IQ scores in this range often have some difficulties with routine cognitive tasks, but are usually able to manage daily life activities with some support.
- 80-89 – Low Average: This range is considered below average. While individuals in this range might struggle with complex cognitive tasks, they usually handle daily life activities without much difficulty.
- 90-109 – Average: This range encompasses the majority of the population (about 50%). Individuals within this range perform cognitive tasks that are typically expected for their chronological age.
- 110-119 – High Average: This range is above average. Individuals with an IQ in this range often show a heightened ability in a variety of tasks and may excel in areas that interest them.
- 120-129 – Superior: This range indicates superior intellectual functioning. Individuals in this range often demonstrate high cognitive abilities and can process complex information quickly and accurately.
- 130 and Above – Very Superior/Extremely High: This range represents the top 2.2% of the population. People with an IQ in this range often have exceptional intellectual abilities and are able to understand and process complex information very quickly.
Each IQ test has its own IQ Score Range. Click below to read more about IQ testing:
SB5 – Stanford-Binet Intelligence Scales, Fifth Edition
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