This is the second installment of my blog series about the History of the IQ Test. Previously I discussed that it was Alfred Binet in 1904 who invented the modern concept of an IQ Test and William Stern in 1912 who first coined the term, IQ.
The original formula used to calculate an IQ score was based largely on the mental age of a person. This formula consisted of 100 times the mental age divided by the chronological age. If the mental age was consistent with the chronological age (meaning the mental age and chronological age were the same), then you would have an IQ score of 100. This is considered to be “normal”. If your score is higher than 100, then your mental age is beyond your years. If you score lower than 100, then you have a lower mental age than what is considered normal for someone your actual age.
Ever wonder where the term, “moron”, came from? Well, it is related to some of the original IQ testing from the early Twentieth century. Goddard, director of the Vineland Training School in New Jersey, used this IQ score concept to classify those of below average intelligence. Those who score below 100 are either categorized as “normal”, “idiots”, or “imbeciles”. According to Goddard idiots have a mental age of 3-7 years old while imbeciles have a mental age below 3 years old. He then coined the term, “moron” to describe someone between the “normal” and “idiot” range. So, calling an imbecile a moron is actually a complement!
Stay tuned for my next installment of the History of the IQ Test where I discuss the test’s progression into what we have come to know as an IQ test today.