Theories of Intelligence in Psychology

While intelligence is one of the most talked about subjects in psychology, there is no standard definition of what exactly constitutes intelligence. Some researchers have suggested that intelligence is a single, general ability. Others believe that intelligence encompasses a range of aptitudes, skills, and talents.

What Is Intelligence?

Intelligence has been a controversial topic throughout psychology's history. Despite the substantial interest in the subject, there is still considerable disagreement about what components makeup intelligence. In addition to questions of exactly how to define intelligence, the debate continues today about whether accurate measurements are even possible.

At various points throughout recent history, researchers have proposed some different definitions of intelligence. While these definitions can vary considerably from one theorist to the next, current conceptualizations tend to suggest that intelligence is the ability to:

Learn from experience: The acquisition, retention, and use of knowledge is an important component of intelligence.

Recognize problems: To put knowledge to use, people must be able to identify possible problems in the environment that need to be addressed.

Solve problems: People must then be able to take what they have learned to come up with a useful solution to a problem they have noticed in the world around them.1

Intelligence involves some different mental abilities including logic, reasoning, problem-solving, and planning. While the subject of intelligence is one of the largest and most heavily researched, it is also one of the topics that generate the greatest controversy.

While psychologists often disagree about the definition and causes of intelligence, research on intelligence plays a significant role in many areas. These areas include decisions regarding how much funding should be given to educational programs, the use of testing to screen job applicants, and the use of testing to identify children who need additional academic help.

Brief History of Intelligence

The term "intelligence quotient," or IQ, was first coined in the early 20th century by a German psychologist named William Stern. Psychologist Alfred Binet developed the very first intelligence tests to help the French government identify schoolchildren who needed extra academic assistance. Binet was the first to introduce the concept of mental age or a set of abilities that children of a certain age possess.2

Since that time, intelligence testing has emerged as a widely used tool that has led to developing many other tests of skill and aptitude. However, it continues to spur debate and controversy over the use of such testing, cultural biases that may be involved, influences on intelligence, and even the very way we define intelligence.

Theories of Intelligence

Different researchers have proposed a variety of theories to explain the nature of intelligence. Here are some of the major theories of intelligence that have emerged during the last 100 years.

General Intelligence

British psychologist Charles Spearman (1863–1945) described a concept he referred to as general intelligence or the g factor. After using a technique known as factor analysis to examine some mental aptitude tests, Spearman concluded that scores on these tests were remarkably similar.

People who performed well on one cognitive test tended to perform well on other tests, while those who scored badly on one test tended to score badly on others. He concluded that intelligence is a general cognitive ability that can be measured and numerically expressed.3

Primary Mental Abilities

Psychologist Louis L.Thurstone (1887–1955) offered a differing theory of intelligence. Instead of viewing intelligence as a single, general ability, Thurstone's theory focused on seven different primary mental abilities.4

Associative memory: The ability to memorize and recall

Numerical ability: The ability to solve arithmetic problems

Perceptual speed: The ability to see differences and similarities among objects

Reasoning: The ability to find rules

Spatial visualization: The ability to visualize relationships

Verbal comprehension: The ability to define and understand words

Word fluency: The ability to produce words rapidly

Theory of Multiple Intelligences

One of the more recent ideas to emerge is Howard Gardner's theory of multiple intelligences. Gardner proposed that the traditional idea of intelligence, based on IQ testing, did not fully and accurately depict a person's abilities. His theory proposed eight different intelligences based on skills and abilities that are valued in different cultures:5

Bodily-kinesthetic intelligence: The ability to control your body movements and to handle objects skillfully

Interpersonal intelligence: The capacity to detect and respond appropriately to the moods, motivations, and desires of others

Intrapersonal intelligence: The capacity to be self-aware and in tune with inner feelings, values, beliefs, and thinking processes

Logical-mathematical intelligence: The ability to think conceptually and abstractly, and the capacity to discern logically or numerical patterns

Musical intelligence: The ability to produce and appreciate rhythm, pitch, and timbre

Naturalistic intelligence: The ability to recognize and categorize animals, plants, and other objects in nature

Verbal-linguistic intelligence: Well-developed verbal skills and sensitivity to the sounds, meanings, and rhythms of words

Visual-spatial intelligence: The capacity to think in images and pictures, to visualize accurately and abstractly

 What Kind of Intelligence Do You Have?

Triarchic Theory of Intelligence

Psychologist Robert Sternberg defined intelligence as "mental activity directed toward purposive adaptation to, selection, and shaping of real-world environments relevant to one's life."

While he agreed with Gardner that intelligence is much broader than a single, general ability, he suggested that some of Gardner's types of intelligence are better viewed as individual talents. Sternberg proposed what he referred to as "successful intelligence," which involves three different factors:6

Analytical intelligence: Your ability to evaluate information and solve problems

Creative intelligence: Your ability to come up with new ideas

Practical intelligence: Your ability to adapt to a changing environment

Questions About Intelligence Testing

In order to gain a deeper understanding of intelligence and the tests developed to measure this concept, it's important to understand the history of intelligence testing, the research that has been conducted, and the findings that have emerged.

Major questions about intelligence and IQ testing still include:

Are intelligence tests biased?

Is intelligence a single ability, or does it involve an assortment of multiple skills and abilities?

Is intelligence inherited, or does the environment play a larger role?

What do intelligence scores predict, if anything?

To explore these questions, psychologists have conducted a considerable amount of research on the nature, influences, and effects of intelligence.