Alfred Binet (1857-1911) developed the first Intelligence Test in collaboration with Theodore Simon, known as the Binet-Simon Scale. The test was developed in order to identify children with learning disabilities so that they might be placed in a special class. The scale was composed of thirty tasks, including items on memory, vocabulary, verbal ability, and reasoning.
The tasks represented typical abilities of children at various ages. A child's score is represented by a "mental age." If a 5-year-old child got a mental age of 7 years old, it would mean that the child was able to pass the items that were normally expected of a 7-year-old child.
The Binet-Simon Scale was later adapted by Lewis Terman in Stanford University, which became known as the Stanford-Binet Intelligence Scale. It has undergone several revisions, and remains to be one of the most widely used IQ Tests today.