Who is credited with the invention of the IQ test?

The invention of the IQ test is primarily credited to Alfred Binet. He developed the first practical intelligence test in the early 20th century, known as the Binet-Simon scale, which aimed to identify students who required additional educational support. This scale laid the foundational concepts for later intelligence tests, including the notion of mental age.

While other individuals, like Lewis Terman, significantly contributed to the development and standardization of intelligence testing in the United States (particularly in adapting Binet's test into what we now recognize as the Stanford-Binet Intelligence Test), the original creation of the IQ test as a concept is attributed to Binet.

Thus, Binet's role in this development is crucial, as it marks the beginning of formal assessments designed to measure intelligence, making him the central figure in the establishment of IQ tests.