On page 1-2 of his excellent 1992 book A Question of Intelligence: The IQ Debate in America, prestigious business journalist Daniel Seligman writes:
Soon after I began outlining this book, I somewhat nervously decided that it was mandatory for me to take an IQ test. I had not confronted one in over forty years…The one I wanted to take was the Wechsler Adult Intelligence Scale, or WAIS, commonly pronounced “wayce.” (There is also the Wechseler Intelligence Scale for Children, or WISC, pronounced “wisk”. )
The WAIS, originally developed by psychologist David Wechsler in the 1950s, was substantially revised in 1981; the revised version is usually described as the WAIS-R. It is far and away the most widely administered adult test today. (The WISC also dominates child testing).
Seligman goes on to explain that he went looking for someone who regularly administers the WAIS-R. I’m sure there were many psychologists who would have leaped at the chance to administer the WAIS-R to an eminent journalist who would mention them by name in a published book. They likely would have performed the testing for free, as the publicity alone would be worth thousands and thousands of dollars. It’s the kind of lucky break that could put a psychologist on the map and make his business a success.
So who was the lucky man? Yaakov Stern, who Seligman described as “a youthful (thirthy-five) amiable , lanky, red-bearded professional wearing a colorful patterned sweater”, based at the Neurological Institute at Columbia-Presbyterian Medical Center in New York city. Seligman writes on page 3:
Chatting with Stern before the test began, I learned something that in years of studying IQ-related issues I had somehow never heard before. It turns out that the test questions, in addition to being copyrighted, are closely guarded–very closely guarded. Even if you are willing to shell out the $350 or so required to buy the Wechsler test kit, it would not be sold to you unless you were a licensed psychologist (like Stern) or had other professional credentials. The restriction is reasonable enough, when you think about it, the point being, of course to keep the questions out of the hands of prospective testees and their mothers…Before turning on my reporter’s tape recorder, I had to agree not to be too precise in characterizing the questions.
You can tell this book was published in 1992 because $350 was considered a lot of money. Today, the latest edition of the WAIS (WAIS-IV) sells for $1,174.00.
The WAIS-R, like it’s predecessor the WAIS, is composed of six verbal subtests and five non-verbal subtests. Raw scores on each of the subtests are converted to scaled scores which range from 1 to 19. The scaled scores are like IQ scores on each particular subtest except instead of having a mean of 100 and a standard deviation of 15, they have a mean of 10 and an SD of 3, so a scaled score of 10 is an IQ equivalent of 100 (on that subtest), a scaled score of 13 is like IQ 115, a scaled score of 16 is like IQ 130, etc. And unlike IQ scores which are calculated relative to one’s own age group, the scaled scores on the WAIS tests were traditionally calculated relative to the peak age group (though on more recent editions, this has changed).
On the WAIS-R, the scaled scores for six verbal subtests are summed and then converted to verbal IQ, and the scaled scores for the five performance subtests are summed and then converted to performance IQ, and then all 11 subtests are summed and converted to full-scale IQ.
The six verbal subtests on the WAIS-R are Information, Similarities, Arithmetic, Vocabulary, Comprehension, and Digit Span.
The five performance subtests are Picture Completion, Picture Arrangement, Block Design, Object Assembly and Digit Symbol.
Anyone who has studied the history of IQ tests can see the huge influence of the World War I IQ tests (Army Alpha and Army Beta) on the structure and subtests of the Wechsler scales.