Spearman's General Intelligence Theory

Charles Spearman

British psychologist, Charles Spearman was one of the first important theorists to tackle the study of human intelligence, introducing an early method of factor analysis. In 1904 he authored his General Intelligence Theory, where all activities share a common general intelligence factor (g). In addition there are also specific abilities (s) that require different levels of this general intelligence.

This theory closely resembles the way intelligence is commonly understood by most people. There is only one intelligence that can be measured, perhaps by IQ tests to measure levels of smartness or not-so-smartness. An accurate test of general intelligence should be culturally unbiased and highly abstract, blocking out many of the specific abilities. For example, an analogy such as cat is to kitten as _____is to puppy does measure the general intelligence (in this case the ability to put together analogies), but also includes specific information. If someone is not familiar with what kittens and puppies are, then this test is not valid.

However, Spearman also states that this analogy would be an accurate measure of one's general intelligence if the subject had knowledge of the specific abilities, in this case if he knew what kittens and puppies were. Since it is not likely that everyone would know what puppies or dogs are, the best tests of general intelligence should involve some form of inductive or deductive reasoning.

One such test is Raven's Progressive Matrices test, which requires the subject to figure out complementary abstract patterns. John Raven worked closely with Spearman in developing this test, which is considered one of the best measures of Spearman's general intelligence. This test has allowed for comparisons across cultures that have been unfeasible under other intelligence tests. Today, with the advent of new computer technology, the reaction time [link to cognitive theories] can also be measured, creating a more accurate measurement of intelligence.