Intelligence: the G Factor and Spearman’s Bifactor Theory

The study of intelligence is one of the topics that attracts most interest. Today we review the G Factor.

The study of intelligence is one of the topics that attracts most interest, and it is easy to guess the reasons why this is so. On the one hand, the ability to adapt to a variety of situations is something that is highly valued in an increasingly demanding labor market that always seeks maximum productivity on the part of the worker.

On the other hand, on a much more subjective level, intelligence has become a defining issue of one's own identity. defining question of one's own identity and affects self-image and self-esteem. However, intelligence may seem too abstract and general a concept to be assimilated by science. How can this problem be addressed from the point of view of psychometrics? psychometrics?

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 perhaps has had more 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 gets very good marks in one subject will also tend to score well in the rest of the subjects. Based on this fact, he devised an explanatory model of intelligence suitable as a starting point for measuring the intelligence quotient (IQ). This explanatory model is called Bifactor Theory of Intelligence.

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

G factor

A general intelligence factorthe so-called G Factorwhich is the essential foundation of intelligent behavior in any situation, no matter how particular it may be.

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 Bifactor Theory can be found in the case of Brain Training video games. These video games seem to be designed to improve our G Factor through play. That is to say, a few hours of play per week should produce the result in the person who plays them of a greater intelligence in any situation. However, it seems that they only act on the S-Factors: one sees an increase in his or her ability when playing, but this improvement does not generalize to other areas, it is a specific learning process whose results do not go beyond the videogame itself..

From abstract to concrete data

We can agree with Spearman in that if anything 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 constantly changing in its adaptation to the different problems we experience: our ability to successfully solve an infinitely varied series of problems with scarce resources (including time). In this sense, it seems necessary to account for something akin to the G Factor.

However, by including such an abstract 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. For this reason, in addition to coining the term G factorSpearman devised a parallel strategy to arrive empirically at concrete values that would define it. Thus, when it came to operationalizing concepts to construct tools for measuring intelligences (the IQ test), the G Factor was G factor is defined as the representation of the variance common to all cognitive tasks measured by the test. This internal structure of the relationships between the data is found through the use of factor analysis.

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

Therefore, the G-factor that is reflected by the tests is actually a quantifiable measure that can only be found by statistical operations. can only be found by means of statistical operations from the raw data collected in each of the test tasks. As opposed to the so-called observable variablesvariables, the Spearman's G Factor shows us a matrix of correlations between variables that can only be found by means of the statistical technique. In other words, it makes visible the structure of relationships between several variables to create a general value that was hidden, the value of the G Factor.

The G-Factor today

Nowadays every intelligence test can be based on different theoretical frameworks and conceptions of intelligenceprecisely because of the abstract nature of the latter concept. However, it is common for these measurement tools to include scores on specific domains of competence (language, spatial intelligence, etc.) at various levels of abstraction, and also to offer a G-Factor as a value summarizing the overall intelligence of the individual. Many intelligence measurement modalities can be considered to be direct descendants of Spearman's theory.

IQ tests claim to measure intelligence psychometrically as a function of genetic or "g" variables. It is an indicator that is often used in academic settings or to detect possible developmental disorders (such as maturational delays) and is also used to establish correlational relationships between the environment and genetic components of intelligence: the G factor has been found to be correlated with life expectancy, employability and other relevant constructs.

Criticisms and discussion

The criticisms that can be made are basically two. The first is that the general intelligence factor seems to be affected by cultural bias. cultural biasThe first is that the general intelligence factor seems to be affected by cultural bias: economic position, educational level, and geographic distribution of housing seem to affect intelligence scores, and this is an issue that cannot be explained by genetic variation alone. The second is that, as practical as it may be, the G Factor is insensitive to the different forms of manifestation of intelligenceThe second is that, as practical as it may be, the G Factor is insensitive to the different manifestations of intelligence, the particularities that make each person develop intelligent behavior in his or her own way (something that Howard Gardner's model of multiple intelligences, for example, has tried to correct).

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