Theories of Intelligence: Spearman to Sternberg Compared

Introduction to Intelligence Paradigms

Theories of intelligence have evolved through a series of paradigms. The major paradigms are psychometrics, cognitive psychology, contextualism, and biological approaches. Below, we compare and contrast Spearman's factor analysis, Thurstone's primary mental abilities, Howard Gardner's theory of multiple intelligences, and Robert Sternberg's triarchic theory of intelligence.

Spearman's Factor Analysis and the General Factor

The first major psychometric theorist was psychologist Charles E. Spearman, who argued that people who performed well on one mental ability test also tended to perform well on others, and that people who did poorly on one test also did poorly on the others.

To confirm this prediction, Spearman devised a technique for statistical analysis that he called factor analysis. By using factor analysis, he was able to examine patterns of individual differences in test scores and identify the underlying sources of those differences. Through his tests, Spearman found that only two kinds of factors underlie all individual differences in test scores. The first and more important factor he named the general factor, or g, which is said to encompass performance on all kinds of tasks requiring intelligence. The second factor is specific to each particular test.

Thurstone's Primary Mental Abilities

In contrast, L. L. Thurstone argued that a single general factor was an artificial product of the way Spearman conducted his factor analysis. Thurstone contended that if the analysis were performed appropriately, seven distinct factors would emerge. These seven primary mental abilities identified by Thurstone were: verbal comprehension, verbal fluency, spatial visualization, inductive reasoning, memory, and perceptual speed.

Gardner's Theory of Multiple Intelligences

Howard Gardner argued that intelligence cannot be reduced to a single factor; instead, he proposed a theory of multiple intelligences. In his view, there are several distinct kinds of intelligence, including linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, and intrapersonal intelligence. Some of these intelligences resemble those proposed by psychometric theorists, while others—such as musical and bodily-kinesthetic intelligence—are not captured by standard psychometric tests. Gardner argued that musical intelligence and bodily-kinesthetic intelligence, the latter of which encompasses the particular faculties of athletes and dancers, represent genuinely distinct cognitive domains.

Gardner derived his framework from a variety of sources, including studies of cognitive processing, brain damage, exceptional individuals, and cognition across cultures. He proposed that his theory is applicable universally.

Sternberg's Triarchic Theory of Intelligence

Although Robert Sternberg agreed with Gardner that intelligence operates at multiple levels, he disagreed with the way Gardner characterized intelligence. According to Sternberg, a theory of intelligence can be adequately mapped onto three integrated components: analytic (academic) intelligence, creative intelligence, and practical intelligence. Because this theory accounts for both cognition and context, it is also known as Sternberg's triarchic theory of human intelligence.

Where Gardner viewed the various intelligences as separate and independent, Sternberg posited three integrated and interdependent aspects of intelligence. These aspects relate intelligence to what goes on internally within a person, to what goes on in the external world, and to experience, which mediates between the internal and external worlds.

The first aspect consists of the cognitive processes and representations that form the core of all thought. Sternberg distinguished three kinds of processes: those involved in deciding what to do and in evaluating how well it was done; those involved in carrying out what one had decided to do; and those involved in learning how to perform the task in the first place.

The second aspect consists of the application of these processes to the external world. According to Sternberg, mental processes serve three functions in everyday life: adaptation to existing environments, shaping of existing environments into new ones, and selection of new environments when existing ones prove unsatisfactory. The theory argues that intelligent persons are not simply those who can execute many cognitive processes quickly. Greater intelligence is reflected in knowing one's strengths and weaknesses, capitalizing on strengths while compensating for weaknesses. In other words, intelligent persons capitalize on a niche where they can work most efficiently.

The third aspect of Sternberg's triarchic theory is the integration of the internal and external worlds through experience. One measure of intelligence is therefore the ability to cope with relatively novel situations by drawing on previously acquired knowledge. For example, Sternberg argues that intelligence might be assessed by taking someone who is well adapted to one culture and placing him or her in an unfamiliar one, in order to evaluate the ability to cope with a new situation.

Conclusion: Comparing the Four Theories

Taken together, these four theories illustrate how conceptions of intelligence have moved from a single unitary construct toward multidimensional, context-sensitive models. Spearman's g factor established a psychometric baseline; Thurstone expanded it into seven primary abilities; Gardner pluralized it into culturally broad, independent intelligences; and Sternberg synthesized multiple dimensions into an integrated, experience-mediated framework. Each subsequent theory responded to perceived limitations in earlier accounts, reflecting the ongoing effort to capture the full complexity of human cognitive ability.