QUESTION OF "GENIUS"
A report from the Supervisory Psychologist
Reprinted from the American Mensa, Ltd Website
Mensa is often considered an "expert" source of information on
intelligence and IQ testing. Dr. Abbie Salny, Mensa's supervisory
psychologist, is the organization's spokesperson on these matters. The
following paragraphs are Dr. Salny's answers to some of the most
frequently asked questions as excerpted from a recent article published
in the Mensa Bulletin, Mensa's monthly member publication.
History of IQ:
The French government had commissioned a man named Binet to devise a test that would enable the school authorities to determine which students "could but wouldn't" and which "just couldn't." Thus, the first intelligence test was born. In the 1920s, Lewis Terman tested hundreds of children in the California public schools. He was a professor at Stanford University and had worked on the American version of the Binet test, which became the Stanford-Binet. At the time, tests were established for each age level. The IQ was determined by dividing mental age by chronological age, moving the decimal point two places to the right, and adding one or two zeros as necessary. This was truly a quotient. However, "IQ" is now a misnomer - the score has been read from a standardized table for the past 60 years. A percentile rank, which Mensa uses, is the correct designation.
different tests qualify for Mensa membership?:
For Mensa, an applicant must achieve a score at the 98th percentile on a standardized, supervised intelligence test or equivalent. The 98th percentile is two standard deviations* above the mean (rounded off). The Stanford-Binet and many school tests have a mean of 100 and a standard deviation of 16, so Mensa's qualifying score is 132. On the other hand, the Cattell IIIB and the Raven's Advanced Progressive Matrices (old form) have a mean of 100 and a standard deviation of 24. Mensa requires a score of 148 for these tests. The score of 148 represents exactly the same 98th percentile. An IQ score means nothing without the name of the test by which it was determined. I read of a woman who said that her son had an IQ of 178. Actually, he had taken the old Cattell IIIB, and that 178 IQ is equivalent to 152 IQ on the Stanford-Binet.
*Standard deviation is a mathematically determined figure to account for variances from the average.
F. Salny, Ed.D.
Supervisory Psychologist, American Mensa
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