What Is General Intelligence (G Factor)?
General intelligence can be defined as a construct that is made up of different cognitive abilities. These abilities allow people to acquire knowledge and solve problems. This general mental ability is what underlies specific mental skills related to areas such as spatial, numerical, mechanical, and verbal abilities. The idea is that this general intelligence influences performance on all cognitive tasks. Psychologist Charles Spearman helped develop a statistical technique known as factor analysis, which allows researchers to use a number of different test items to measure common abilities. For example, researchers might find that people who score well on questions that measure vocabulary also perform better on questions related to reading comprehension. However, because this person is athletic and fit, they will probably perform much better on other physical tasks than an individual who is less coordinated and more sedentary. In 1904, he suggested that this g factor was responsible for overall performance on mental ability tests. He noted that while people certainly could and often did excel in certain areas, people who did well in one area tended also to do well in other areas.
Components of General Intelligence
There are several key components that are believed to make up general intelligence. these include:
Fluid reasoning: This involves the ability to think flexibly and solve problems. Knowledge: This is a person’s general understanding of a wide range of topics and can be equated with crystallized intelligence. Quantitative reasoning: This involves an individual’s capacity to solve problems that involve numbers. Visual-spatial processing: This relates to a person’s abilities to interpret and manipulate visual information, such as putting together puzzles and copying complex shapes. Working memory: This involves the use of short-term memory such as being able to repeat a list of items.
How Is It Measured?
Many modern intelligence tests measure some of the cognitive factors that are thought to make up general intelligence. Such tests propose that intelligence can be measured and expressed by a single number, such as an IQ score. The Stanford-Binet, which is one of the most popular intelligence tests, aims to measure the g factor. In addition to providing an overall score, the current version of the test also offers a number of score composites as well as subtest scores in ten different areas.
Impact
While the concept of intelligence is still the subject of debate within psychology, researchers believe that general intelligence is correlated with overall success in life. Some of the effects that it may have on an individual’s life include areas such as:
40 - 54: Moderately impaired or delayed 55 - 69: Mildly impaired or delayed70 - 79: Borderline impaired or delayed80 - 89: Low average intelligence90 - 109: Average110 - 119: High average120 - 129: Superior130 - 144: Gifted or very advanced145 - 160: Exceptionally gifted or highly advanced
Academic Achievement
One of the most obvious effects of general intelligence is in the realm of academic performance. While intelligence plays a role in academics, there has been a great deal of debate over the extent to which it influences academic achievement. Research has shown that there is a strong association between general mental ability and academic achievement, but it doesn’t act on its own. Some research suggests that between 51% and 75% of achievement cannot be accounted for by g factor alone.
Job Success
IQ scores have long been thought to correlate to career success. This is why psychological testing has become so prevalent for pre-employment screening and career placement. Many have questioned, however, whether a general mental ability was really more important than specific mental abilities. A 2020 study published in the Journal of Applied Psychology concluded that both general intelligence and specific mental abilities play an important role in determining career success including income and job attainment. The importance of g factor for job success becomes greater as the complexity of the work increases. For occupations with a high degree of complexity, having a higher general intelligence becomes a greater asset.
Health and Longevity
The field of cognitive epidemiology looks at associations between general intelligence and health. Just as health can play a role in influencing intelligence, a person’s intelligence may have an impact on their health. Studies have found that high IQ individuals have a lower risk of:
Coronary heart diseaseHypertensionObesityStrokeSome cancers
Income
Research also suggests that people with higher intelligence scores also tend to earn higher incomes. However, it is important to note that other factors play a mediating role including education, occupation, and socioeconomic background. While g factor has a number of effects, other variables are also important. Factors such as socioeconomic status and emotional intelligence, for example, can interact with general intelligence and play a major part in determining a person’s success.
Challenges
The notion that intelligence could be measured and summarized by a single number on an IQ test was controversial even during Spearman’s time. IQ and intelligence testing have remained topics of debate ever since. While influential, g factor is just one way of thinking about intelligence.
Thurstone’s Primary Mental Abilities
Some psychologists, including L.L. Thurstone, challenged the concept of a g-factor. Thurstone instead identified a number of what he referred to as primary mental abilities:
Associative memoryNumber facilityPerceptual speedReasoningSpatial visualizationVerbal comprehension
He suggested that all people possess these mental abilities, although to varying degrees. People could be low in some areas and high in others.
Gardner’s Multiple Intelligences
More recently, psychologists such as Howard Gardner have argued against the notion that a single general intelligence can accurately capture all of human mental ability. Gardner instead proposed that multiple intelligences exist.
A Word From Verywell
Research today points to an underlying mental ability that contributes to performance on many cognitive tasks. IQ scores, which are designed to measure this general intelligence, are also thought to influence an individual’s overall success in life. However, while IQ can play a role in academic and life success, other factors such as childhood experiences, educational experiences, socioeconomic status, motivation, maturity, and personality also play a critical role in determining overall success.
