“Inequalities of Children in Original Endowment”: How Intelligence Testing Transformed Early Special Education in a North American City School System

“There are few if any more significant events in modern educational history than the developments which have recently taken place in methods of mental measurement,” Lewis Terman wrote in 1923 about the intelligence testing movement he did so much to pioneer in American schools throughout the 1920s. Indeed educational historians, particularly Paul Chapman, have shown that the rise of intelligence testing provoked large and relatively swift changes in public education, enabling school systems to sort and stream their students by ability on an unprecedented scale. “By 1930,” Chapman writes, “both intelligence testing and ability grouping had become central features of the educational system.” Less often talked about are the effects of intelligence testing and the concept of intelligence quotient (IQ) on early special education classes, and on the pupils who attended them. In fact, Terman recognized the significance of IQ testing to special education as well. In 1919, he wrote that IQ tests would help to turn the existing logic of learning problems on its head by proving that “the retardation problem is exactly the reverse of what it is popularly supposed to be.”