“Alfred Binet was commissioned by the minister of public education in France to devise a way of identifying students in primary school whose difficulties in normal classrooms suggested some need for special education. Binet specifically denied the test—later called an intelligence quotient (or IQ) when the German psychologist W. Stern scored the results by dividing ‘mental age’ (as ascertained on the test) by chronological age—could be measuring an internal biological property worthy of the name “general intelligence.” First of all, Binet believed that the complex and multifarious property called intelligence could not, in principle, be captured by a single number capable of ranking children in a linear hierarchy. He wrote in 1905:
‘The scale, properly speaking, does not permit the measure of the intelligence because intellectual qualities are not superposable, and therefore cannot be measured and linear surfaces are measured.’
Moreover, Binet feared that if teachers read the IQ number as an inflexible inborn quality, rather than (as he intended) a guide for identifying students in need of help, they would use the scores as a cynical excuse for expunging, rather than aiding, troublesome students. Binet wrote of such teachers: “The seem to reason in the following way: ‘Here is an excellent opportunity for getting rid of all the children who trouble us,’ and without the true critical spirit they designate all who are unruly, or disinterested in the school.” Binet also feared the powerful bias that has since been labeled “self-fulfilling prophecy” of the Pygmalion effect: if teachers are told that a student is inherently uneducable based on misinterpretation of low IQ scores, they will treat the student as unable, thereby encouraging poor performance by their inadequate nurture, rather than the student’s inherent nature. Invoking the case then wracking France, Binet wrote:
‘It is really too easy to discover signs of backwardness in an individual when one is forewarned. This would be to operate as the graphologists did who, when Dreyfus was believed to be guilty, discovered in his handwriting sign or a traitor or a spy.’
Binet felt that this test could be used to identify mild forms of retardation or learning disability. Yet even for such specific and serious difficulties, Binet firmly rejected the idea that his test could identify causes of educational problems, particularly their potential basis in biological inheritance. He only wished to identify with special needs, so that help could be provided:
‘Our purpose is to be able to measure the intellectual capacity of a child who is brought to us in order to know whether he is normal or retarded…..We shall neglect his etiology, and we shall make no attempt to distinguish between acquired and congenital [retardation]….We do not attempt to establish or prepare a prognosis, and we leave unanswered the question of whether this retardation is curable, or even improvable. We shall limit ourselves to ascertaining the truth in regard to his present mental state.'”
Gould, Stephen Jay. The Mismeasure of Man. New York: W.W. Norton, 1996.