Intelligence Is Best Explained by the Concept of G - Essay Example

Intelligence is Best Explained by the Concept of 'G' If we were to look in any diction we would see that intelligence is defined as "the capacity for learning, reasoning, understanding and similar forms of mental activity" ("Intelligence" 2006, 1). This definition is, however, incomplete. Although it tells us, more or less, what intelligence does, it does not explain the inter-workings of intelligence - the why This very question prompted Charles Spearman at the turn of the 20th century to investigate exactly what intelligence is and how it can be measured. Charles Spearman is considered to be the 'Father of Classical Test Theory'. During his career in psychology which was rooted in an engineering base, Spearman became enraptured in understanding intelligence and more importantly what makes up intelligence. On his road to achieve this Spearman developed Factor Analysis a statistical analysis method to determine if there were correlations between independent factors. In 1904, Spearman published "General Intelligence, Objectively Measured and Observed" in which the first scientific definition of intelligence was put forth. According to Spearman, intelligent behaviour is generated by a single, unitary quality within the human mind or brain. Spearman derived this theoretical entity, called the general factor, or simply g, through a new statistical technique that analyzed the correlations among a set of variables. This technique, called factor analysis, demonstrated that scores on all mental tests are positively correlated; this offered compelling evidence that all intelligent behaviour is derived from one metaphorical pool of mental energy" ("Charles" 2007, 1). In short, Spearman's Theory of General Intelligence states "all variation in intelligence test scores can be explained by two factors. The first is the factor specific to an individual mental task: the individual abilities that would make a person more skilled at one cognitive task than another. The second is g, a general factor that governs performance on all cognitive tasks" (History 2007, 1). Researchers have long agreed that there is a wide range of ability in basic cognitive skills such as logical reasoning, spatial analogies, completion of matrices, vocabulary and other mental tests among different people. The same people tend to do better on these tests across the entire range of tests than do other people. Further, by use of statistical analysis of this raw data, researcher have isolated the cause for the differences in people's mental reasoning abilities to one factor credited for this consistent accelerated performance - that one factor is 'g'. G acts like a correlation coefficient with a value of .65 (Flynn 2003). Jensen (2002) reported that individuals with higher levels of g, in effect, have better brains. People with these higher levels of g tend to prefer more complex cognitive tasks resulting in high g loading. To explain this Jensen (2002, 153) states: "some property of the brain has cognitive manifestations that result in the emergence of g." In effect, Jensen (2002) asserts that g is a measure of the influence on brain quality. The higher the g; the 'better' the brain; this result equates to an advantage in any cognitive skill utilized. Johnson et al. (2004) conducted a study to determine whether g, in actuality, predicts a wide range of cognitive performances. The researchers predicted that Spearman's g would have a strong correlation on a diverse set of abilities. The empirical evidence proving the existence of g is well documented. However, there remains some controversy in that "the social implications of the existence of measurable individual differences in a personal characteristic that is highly predictive of a broad range of life outcomes" (Johnson et al. 2004, 96). The researchers assert that regardless of the battery of tests utilized to measure g, the results should be uniform across various test batteries. If, in fact, g varies across these different kinds of test batteries, the measurement of g becomes arbitrary. In effect, there would exist multiple g's depending upon the battery of tests being used. In order to prove that g can be extracted across multiple test batteries, Johnson et al. (2004) conducted a study utilizing 436 participants, all of whom were members of the Minnesota Study of Twins Reared Apart (MISTRA). Ages ranged between 18 and 79 with a mean age of 42.7 years. The participants came from varied backgrounds, geographic locations, socioeconomic status, educational level and occupations. The study utilized three different test batteries: The Comprehensive Ability Battery (CAB), which consists of 20 primary ability tests; The Hawaii Battery (including Raven's Progressive Matrices) which consists of 15 primary ability tests; and the Weschler Adult Intelligence Scale (WAIS) which consists of 11 primary ability tests. Upon completion of the testing Johnson et al. (2004) found after independent statistical analysis of each of the three battery tests there was virtually no difference in the g factor extracted even though the primary ability tests measured in each battery types were not identical. Johnson et al. (2004, 104) stated that "These results provide the most substantive evidence of which we are aware that psychological assessments of mental ability are consistently identifying a common underlying component of general intelligence." There are critics to the theory of general intelligence factor, most typically those favouring various models intelligence theories. These theories are based on the precept that g is not the sole or even primary cause of intelligence. One such variable theory was put forth by Sternberg et al. (2000), the Triarchic Theory of Intelligence. This theory is based on the precept that there exists in addition to the g factor (general intelligence), practical intelligence. While g accounts for the more cognitive 'school' functioning, practical intelligence is seen in the more practical activities of life. Sternberg et al. (2000) asserts that practical intelligence is a better indicator of future success than is the g factor - general intelligence. Gottfredson (2003, 344) asserts that claims such as those made by Sternberg overlook the vast amount of empirical data proving that: g forms the common backbone of all mental abilities; and important because, if true, it would require a major reorientation in scientific thinking on intelligence. Their summaries of the research can seem impressive at first glance, but the work itself has received little scrutiny from mainstream intelligence researchers. Gottfredson (2003) concludes by stating that the massive amount of empirical data proving the importance of the g factor as a high level general mental ability with a basis in genetics creates each of us in a highly unique manner. Sternberg et al. (2000) have by no means provided any strong empirical data to disprove the importance of g, let alone to show that performance intelligence is, in fact, a better indicator of success. In closing Gottfredson (2003, 392) reminds us: It is true that g provides only a partial explanation of ''intelligent behavior,'' and that its role in everyday affairs is yet poorly understood. But there is a solid, century-long evidentiary base upon which researchers are busily building. Simply posting a new and independent intelligence to explain much of what remains unexplained (and much of what has already been explained), while simultaneously ignoring the ever-growing evidentiary base, does not promise to advance knowledge. Visser, Ashton and Vernon (2006) conducted a study to disprove Gardner's Theory of Multiple Intelligences which rather than embracing the commonly accepted notion of general intelligence (g) put forth the notion that intelligence was instead also expressed as a result of three independent factors, experience, culture and motivation. Gardner defines intelligence as "the ability to solve problems and to fashion products that are culturally valued" (as cited in Visser, Ashton & Vernon 2006, 487). Gardner believes that there are eight intelligences: linguistic, spatial, logical/mathematical, interpersonal, intrapersonal, bodily-kinesthetic, musical and naturalistic. Although he readily admits that many of these intelligences may be viewed as talents, he contends that one is no less important than another; therefore, intelligences such as linguistics and mathematics contain no more real-life importance than do any of the other intelligences. In order to investigate the relationship between Gardner's eight intelligences Visser, Ashton and Vernon (2006) conducted a study utilizing 200 participants. These participants underwent eight different batteries to test for each of Gardner's intelligences. After statistical analysis of the data, the researchers concluded that there was a strong correlation between many of the test findings. Additionally, throughout there was a consistent, strong g factor present which is inconsistent with Gardner's theory. A g factor should only be present when there is a high level of verbal demands necessary for a particular battery. The researchers in this study selected their battery tests which required minimal, and in some cases, no verbal prompting. Therefore, if the Multiple Intelligences Theory is correct no g factor should have been present. Although the g factor remains controversial to many theorists, it has proven empirically throughout the last century to be a statistically consistent. The human mind is very complex and we are just beginning to understand how it functions and inter-relates. Although general intelligence and g factor may not be the only factor which affects intelligence, it is by far the one aspect of intelligence research that has been consistently replicated. Works Cited "Charles Spearman" Human Intelligence. 2007. University of Indiana Website. Retrieved April 29, 2007 from . Flynn, James R. "Movies about Intelligence: The Limitations of g" Current Directions in Psychological Science 12.3 (June 2003): 95-9. Gottfredson, Linda S. "Dissecting Practical Intelligence Theory: Its Claims and Evidence" Intelligence 31 (2003): 343-97. "History of g." Wikipedia website. 2007. Retrieved 29 April 2007, from . "Intelligence." Dictionary.com Unabridged (v 1.1). Random House, Inc. 01 May. 2007. . Jensen, A. R. "Galton's legacy to Research on Intelligence" Journal of Biosocial Science 34 (2002): 145-72. Johnson, Wendy et al. "Just one g: Consistent Results from Three Test Batteries" Intelligence 32 (2004): 95-107. Spearman, C. (1904) "'General Intelligence' Objectively Measured and Determined." May 2000. Classics in the History of Psychology Website. Retrieved April 29, 2007 from http://psychclassics.yorku.ca/Spearman/chap1-4.htm Sternberg, R. J. (2000). Practical Intelligence in Everyday Life. New York: Cambridge University Press. Visser, Beth A., Michael C. Ashton and Philip A. Vernon. "Beyond G: Putting Multiple Intelligences Theory to the Test" Intelligence 34 (2005): 487-502. Read More