Intelligence: the G Factor and Spearman's Bifactorial Theory - psychology - 2023



The study of intelligence is one of the topics that attracts the most interest, and it is easy to assume the reasons why this is so. On the one hand, the ability to adapt to varied situations It is something that is considered a lot in an increasingly demanding job market that always seeks maximum productivity from the worker.

On the other hand, on a much more subjective level, intelligence has become a defining question of one's identity and that affects self-image and self-esteem. Now, intelligence may seem too abstract and general a concept to be grasped by science. How is this problem tackled from the psychometry?

The two factors of intelligence

In the study of intelligence there are different paradigms, such as fluid intelligence and crystallized intelligence. However, it is the Bifactorial Theory of the English psychologist Charles spearman (1863 - 1945) the one that has perhaps had the most notoriety historically.

Spearman observed that the scores that school-age children obtained in each of the subjects showed a direct relationship, so that a schoolchild who obtains very good grades in one subject will also tend to score well in the rest of the subjects. Based on this fact, he devised an explanatory model on intelligence suitable to be a starting point for measuring the I.Q (CI). This explanatory model is called Bifactorial Intelligence Theory.

According to this theory, intelligence, which is the theoretical construct that is measured by tests in the form of IQ, has two factors:

G factor

A general factor of intelligence, the call G factor, which is the essential foundation of intelligent behavior in any particular situation.

S factors

A series of specific factors, which can be understood as abilities and aptitudes that are present only in certain areas of life and whose results cannot be generalized to other domains.

A good example to explain the Bifactorial Theory can be found in the case of Brain Training video games. These video games appear to be designed to improve our G Factor through play. That is, a few hours of play a week would have to produce the result in the person who plays them with greater intelligence in any situation. However, it seems that they only act on the S Factors: one sees an increase in their ability to play, but this improvement is not generalized to other areas, it is a specific learning whose results do not go beyond the video game itself.

From the abstract to the concrete data

We can agree with Spearman that if something characterizes intelligence, it is its abstract nature. In the study of intelligence there is the paradox of trying to explain something that is defined by changing all the time in its adaptation to the different problems that we live: our ability to successfully solve the infinitely varied series of problems with scarce resources (among them , time). In this sense, it seems necessary to account for something similar to G factor.

Now, by including an abstract dan concept as the general factor of intelligence, this theoretical model becomes impractical if it is not based on concrete data, on what we find empirically through IQ measurements. Therefore, in addition to coining the term G factor, Spearman devised in parallel a strategy to arrive empirically at concrete values ‚Äč‚Äčthat would define it. Thus, when it comes to operationalize concepts to build intelligence measurement tools (the IQ test), the G factor it is defined as the representation of the variance common to all the cognitive tasks that are measured by the test. This internal structure of the relationships between the data is found through the use of factor analysis.

Speraman believed that intelligence consisted of knowing how to perform a series of tasks and that the most intelligent people knew how to do all tasks well. The different tasks he proposed in the IQ test could be organized into three groups (visual, numerical and verbal), but all of them were correlated. This last factor, resulting from the study of these correlations, would be significant.

Therefore, the G Factor that is reflected by the tests is actually a quantifiable measure that can only be found by statistical operations from the raw data collected in each of the test tasks. In opposition to calls observable variables, the G factor Spearman's shows us a matrix of correlations between variables that can only be found using the statistical technique. That is, it makes the structure of relationships between various variables visible to create a general value that was hidden, the value of the G factor.

The G Factor, today

Today each intelligence test can be based on different theoretical frameworks and conceptions of intelligenceprecisely because of the abstract nature of this last concept. However, it is common for these measurement tools to include scores on specific areas of competence (language, spatial intelligence, etc.) at various levels of abstraction, and to also offer a G-Factor as a value that summarizes the general intelligence of the individual. Many modes of intelligence measurement can be considered to be direct descendants of Spearman's theory.

The IQ tests are intended to measure intelligence psychometrically based on genetic variables or "g". It is an indicator that is usually used in academic settings or to detect possible developmental disorders (such as maturational delays) and is also used to establish correlation relationships between the environment and the genetic components of intelligence: the G factor has been correlated with life expectancy, the possibility of finding work and other relevant constructs.

Criticism and discussion

The criticisms that can be made are basically two. The first is that the general intelligence factor seems to be affected by the cultural bias: the economic position, the educational level and the geographic distribution of the house seem to affect the intelligence results, and this is a question that cannot be explained only by genetic variation. The second is that, as practical as it may be, the G Factor is insensitive to the different forms of manifestation of intelligence, the particularities that make each person develop intelligent behavior in their own way (something that has been tried to be corrected from Howard Gardner's model of multiple intelligences, for example).

Either way, it is clear that the G Factor is a very interesting concept for research in psychology and social sciences.