“Intelligence” is one of those words that we use often but have a very hard time defining. While phrenologists like Gall thought they could use head lumps to measure various aspects of intelligence, modern researchers have used paper-and-pencil tests, problem-solving tasks, and even brain scans to study cognitive capacities.

So what would you, as a psychologist, select as your operational variable(s) for the conceptual variable of intelligence?

Is There Such a Thing as A General Intelligence?

The most widely known operationalization of the concept of a single, general intelligence evolved from Alfred Binet (1857-1911), a French psychologist. The test has since been revised and is now known as the Stanford-Binet test, though there are other forms measures, like the Wechsler tests, that are more common today. 

Do not trust everything you find online that is labeled as an IQ test… if the test is not administered in a controlled and standardized way, the results cannot be taken seriously (no matter how intelligent the test says you are).

The common idea here is that there is such a thing as an overall level of general intelligence, even though the individual items on an IQ test measure different forms of reasoning and problem solving.  Charles Spearman (1863-1945) called this general intelligence the g factor, some core level of basic intelligence that underlies all other specific abilities.  The idea of g is easy for people to relate to because we often think about some people as being particularly "smart" and others, well, less so.

Multiple Forms of Intelligence

While some have focused on measuring the g factor, other theorists have proposed that there are actually several different types of intelligences that are not necessarily correlated with each other. That is, a person can be strong in a couple types and weak in others. Howard Gardner’s Theory of Multiple Intelligences is among the more popular, but we will not go into detail on it here.  However, just to give you an example, he suggested that one person with strong logic-math and spacial-visual intelligence would be a chess expert while another person with strong bodily-kinesthetic intelligence would be an Olympic athlete.

Gardner's theory is appealing to many because in our lives we experience differences between people, and we would like to think that we are each "intelligent" in our own way.  However, it is important to note that there is still a debate with regards to whether these should really be thought of as unique types of intelligence or simply different strengths that are still largely determined by g and experience (did your parents give you puzzles or sports equipment to play with?).  Critics also point out that the list could go on forever if we consider every way in which we might be different from each other.  For example, should we consider taste a form of intelligence if you are able to tell the difference between expensive and cheap coffee in a taste test?

Although Gardner comments that our intelligences influence our learning preference, he also insists that the concept was never intended to (nor does it) provide any scientific evidence that people truly have different learning styles (Gardner, 2013) [PDF].

Back to Unit 02 - Cognition, Intelligence & Memory