Intelligence

Though most people think of intelligence as a familiar concept, many experts consider it a very controversial subject.  Few of them agree on an exact definition or on one theory related to identifying and quantifying important aspects.

Many investigators believe that intelligence is made of several mental abilities, or factors.  British psychologist, Charles Spearman (1904) suggested that the behaviors we consider intelligent have a common underlying factor.  He believed that people have general intelligence, or broad reasoning and problem-solving abilities, he labeled this factor “g.”  He also believed that some people have specific intelligence, or abilities in areas like business, math, poetry, music, etc., he called this factor “s.”  Spearman developed factor analysis in order to test his theory.  This statistical technique allows researchers to figure out which items on an intelligence test seem to be measuring the same things.  In his research on relationships among test scores in verbal, mathematical, and spatial reasoning, he repeatedly found evidence supporting the existence of s intelligence.  He found much less evidence supporting the g intelligence.  Louis Thurstone (1938) tested factor analysis and found similar results.  Thurstone came to the conclusion that Spearman had oversimplified the concept of intelligence.  He then came up with the view that people could excel in some areas, but be average in others.  This view made sense to psychologists.  Though Thurstone used only nine intelligence factors, psychologist J. P. Guilford (1988) expanded on this and came up with hundreds of factors.  The only thing wrong with this was that too many of these factors overlapped.

Another intelligence theory is Gardner’s Theory of Multiple Intelligences.  Howard Gardner (1983) proposed the existence of seven kinds of intelligence: language, musical, logical-mathematical, bodily-kinesthetic talent, interpersonal skills, intrapersonal skills, and spatial-relations skills.  Gardner also believed that each kind of intelligence has a neurological base in different areas of the brain.  Critics of Gardner’s theory will generally agree that people function better in some areas than others, but many disagree as to whether talents (musical, bodily-kinesthetic) should be included with actual intelligences (logical-mathematical, language).

Yet another intelligence theory is Sternberg’s Triarchic Theory.  There are three kinds of intelligences in this theory; Componential Intelligence, Experimental Intelligence, and Contextual Intelligence (Sternberg, 1985).  Componential Intelligence is academic ability and is characterized by the abilities to; solve problems, compare and contrast, judge, evaluate, and criticize.   Experimental Intelligence is creative ability and is characterized by the abilities to; invent, discover, suppose, and theorize.  Contextual Intelligence is practical ability and is characterized by the abilities to; adapt to the demands of one’s environment, and apply knowledge in practical situations.

Peter Salovey and John Mayer developed another theory, the Theory of Emotional Intelligence.  This theory holds that self-awareness, self-control, empathy, cooperation, etc. are all forms of intelligence.  This has been a highly debated theory because not everyone agrees that emotions should be considered forms of intelligence. As Ulrich Neisser (1997) said, “these skills . . . are certainly important for determining life outcomes, but nothing is to be gained by calling them forms of intelligence.”

Another questionable element of intelligence was its stability.   People wondered did it decrease with age?  Increase?  At first, the cross-sectional method of research was used.  Researchers took random samples of people from various age groups, all at one time (Philipchalk & McConnell, 1994).  They found that the older the person, the lower the IQ score.  They drew the conclusion that as age increases, IQ decreases.  But as researchers became more curious about how much age affected IQ they decided to perform longitudinal studies of intelligence.  Longitudinal studies are those which involve testing individuals at various points in their lives.  The results surprised many people, IQ scores did not decrease with age!  These results were not accepted at first, because it was unbelievable.  They became more accepted after the introduction of Cattell’s theory of fluid and crystalized intelligence.  This theory held that fluid intelligence (the ability to take in information and deal with it quickly) declined with age, but that crystalized intelligence (accumulated knowledge and experience) did not.  This caused the results of the longitudinal studies of intelligence to become more widely accepted.

There are also several definitions of intelligence given by numerous experts.  Most psychologists will agree that intelligence has something to do with providing the cognitive basis for academic achievement (Rathus, 1999).  But they will not agree on a single definition as being the most acceptable.

Now if we were to look up intelligence in the dictionary, we could come up with an answer like, “inborn quickness of understanding” (Webster’s, 1978, p. 196).  According to this dictionary, which is quite obviously out of date, intelligence is entirely hereditary.  This is no  longer considered an acceptable definition.  In a slightly more up-to-date dictionary the definition is, “the faculty of understanding : capacity to know or apprehend, the ability . . . to use one’s existing knowledge to meet new situations and solve new problems” (Webster’s, 1981).  This particular dictionary goes on for almost another half page about what intelligence is!  The definition changed quite a lot during the three short years between these dictionaries.