Under the Microscope: Sir Francis Galton (1822-1911), was the first person to seriously consider the matter of whether human intelligence could be tested, writes Prof William Reville.
Galton, who was a cousin of Charles Darwin, spent much of his life investigating the relationship between heredity and human ability. Since Galton's time, the testing of human intelligence has had an active and sometimes controversial history. Galton believed that mental traits are inheritable, just like hair or eye colour. He published his ideas in a book called Hereditary Genius, the first scientific study of intelligence. Further details at
http://www.testcafe.com/iqtest/history.html.
In the meantime, a French psychologist called Alfred Binet (1857-1911) devised tests to rate child intelligence. He worked with average and mentally handicapped students and identified certain tasks within the competence of average but not of handicapped students. Binet correlated normal abilities with age for students and could calculate how many years a student's mental age was below or above the norm.
The French educational authorities asked Binet to develop a test to separate normal children from special needs students. These tests became very popular. In 1912 a German psychologist, Wilhelm Stern, proposed a better way of expressing the results of the Binet test than by mental age. Stern expressed his results as the ratio between a subject's chronological age and their mental age. For example, a ten-year-old scoring two years ahead of his chronological age would be assigned a score of 120, and a five-year-old scoring one year ahead of his chronological age would also be assigned a score of 120.
The American psychologist Louis Terman introduced the term intelligence quotient (IQ) for Stern's scoring method. One hundred was taken as an average IQ score. A score above 100 was deemed above average, and a score below 100 was deemed below average.
Both Binet and Stern recognised that the Binet test had limitations and doubted that the IQ score reflected a fixed inborn quota of intelligence. Nevertheless, this Binet test was accepted enthusiastically, particularly in the US. IQ testing received a massive boost when the US entered the first World War in 1917 and the army had to match large numbers of draftees with various army positions. A group intelligence test was developed and was taken by almost two million men by 1919.
Many companies began using IQ tests to help determine hiring, promotion and transfer. They also became popular in schools. Nevertheless, IQ testing was not without critics and some social commentators pointed out that these tests could cruelly label a child as inferior at a very early age. IQ tests began to fall out of favour in the US in the 1960s and the 1970s, in part, at least, because of claims that many test questions were racially and culturally biased.
General understanding of intelligence has evolved. Howard Gardner declared in 1983 that "reason, intelligence, logic and knowledge are not synonymous". He proposed a theory of multiple intelligences and defined seven different intelligences: logical-mathematical, linguistic, musical, spatial, bodily kinaesthetic, interpersonal and intrapersonal.
Gardner's is a much broader concept of intelligence than the traditional idea of intelligence from a mathematical and verbal understanding. and his ideas are becoming popular. Hoever, traditional methods of intelligence testing are still widely used.
Let me finish by giving you a test devised by MENSA that originated in South Africa. It contains 34 items numbered from 0 to 33. You are given the answer to item 0 to show how the test works. The test, e-mailed to me by a friend, bore the following legend: "You have to work out what the letters mean. According to MENSA if you get 23 of these, you are a genius. Only three MENSA members achieved full marks."
The test now follows. (0) 24 H in a D. Answer: 24 hours in a day. (1) 26 L of the A. (2) 7 D of the W. (3) 7 W of the W. (4) 12 S of the Z. (5) 66 B of the B. (6) 52 C in a P (W Js). (7) 13 S in the USF. (8) 18 H on a G C. (9) 39 B of the O T. (10) 5 T on a F. (11) 90 D in a RA. (12) 3 B M (S H T R). (13) 32 is the T in D F at which W F. (14) 15 P in a R T. (15) 3 W on a T. (16) 100 C in a D. (17) 11 P in a F (S) T. (18) 12 M in a Y. (19) 13=UFS. (20) 8 T on an O. (21) 29 D in F in a L Y. (22) 27 B in the N T. (23) 365 D in a Y. (24) 13 L in a B D. (25) 52 W in a Y. (26) 9 L of a C. (27) 60 M in an H. (28) 23 P of C in the H B. (29) 64 S on a C B. (30) 9 P in S A. (31) 6 B to an O in C. (32) 1000 Y in a M. (33) 15 M on a D M C.
MENSA (Ireland) tells me that this test is not designed to vet applicants for membership of MENSA. Details of how to join Irish MENSA can be had by contacting admin@mensa.ie or by writing to Irish MENSA, PO Box 3647, Dublin 4.
I'm not sure what this test measures, but I found it great fun to do. I gave the test to college student Clare L. who got most of it out in an hour (Solution next week).
William Reville is associate professor of biochemistry and director of microscopy at University College Cork