Spearman (1904) was one of the first researchers to introduce general intelligence, commonly known as the “g” factor. Spearman (1904) believed that the “g” factor was the reason for performance on mental ability tests. Spearman (1904) had also stated that individuals who performed well in a certain area also excelled in other areas. For example, a person who performed well on a math test would also perform well on other tests. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay After the work of Spearman (1904), came Thurstone (1934), who believed that Spearman's (1904) theory was limited due to the fact that the variables only had "g" in common . Thurstone (1934) suggested that hat intelligence came from seven abilities, as opposed to abilities resulting from the “g” factor, as Spearman (1904) had imposed. The seven abilities introduced by Thurstone (1934) are: verbal comprehension, word fluency, facility with numbers, spatial visualization, associative memory, perceptual speed and reasoning. These mental abilities, explained by Thurstone (1934), are primary mental abilities necessary for a person to succeed in their environment. However, another researcher, Cattell (1971) agreed with the work of Spearman (1904) regarding the existence of a "g" factor and disagreed with the work of Thurstone (1934). Indeed, Cattell (1971) maintains that intercorrelations imply the existence of a global “g” factor. Cattell's (1971) theory is slightly different from Spearman's (1904) theory, in that Cattell (1971) proposes that "g" can be achieved through two factors; crystallized intelligence (Gc) and fluid intelligence (Gf). Gc is that of skills and knowledge acquired over a long period of time. Gf is an individual's reasoning ability, which is natural and grows with the individual into adulthood. General Mental Ability (GMA) tests are used during job interviews to measure an individual's skills and personality. These tests are considered good indicators of how new hires will perform on the job in most work environments. GMA tests tend to be more accurate in predicting job performance with more complex job roles. The link between GMA and job performance is stronger when the employee has a lot of experience in the field. If a new hire learns the role faster than another employee with the same experience, there is a greater chance that the person who learned faster will perform better. It is therefore essential to test the candidate's skills, even if they have previous experience. Although GMA is considered a powerful indicator of job performance, research shows that the correlation between GMA and job performance weakens over time (Keil and Cortina 2001). . This is because when new hires start out, they focus more on being able to learn the basic tasks and duties that their role entails. As they gain more experience and understanding of their work, the need for job-specific development diminishes. Therefore, they rely less on GMA to perform their role and instead depend on their individual characteristics, such as personality, to meet their job requirements. However, this does not mean that GMA will become useless; there may be more important factors that.