History Of The Concept Of Intelligence Research Paper

1. Species, Groups, And Intelligence

Although human nature had become a topic of hot concern in the eighteenth century, of relevance not only to the emerging human sciences but also to many of the most important developments in political philosophy as well, this did not at first spur much interest in intelligence. Rather, the focus tended to be on other concepts, on ‘faculties,’ ‘talents,’ ‘sensations,’ and, most especially, ‘reason’ and ‘virtue.’ While it is clear that there was widespread agreement that human beings differed in their mental powers, the origin, significance, and even the sheer number of those differences were all issues that elicited either a multitude of opinions, or no particular view whatsoever. In general, single all-encompassing approaches to understanding mental capacity, such as ‘intelligence,’ tended to be used only in limited and very particular contexts.

Intelligence began to become an object of direct scientific investigation toward the end of the eighteenth century, when such naturalists as Linnaeus, Buffon, and Blumenbach developed taxonomic schemes that compared human beings systematically with the rest of the animal kingdom, often focusing in part on differences in overall levels of mental ability. The Dutch anatomist and artist Peter Camper, for example, proposed in the 1760s that a scale of intelligence across the animal kingdom could be erected on the basis of a particular physiological feature, the facial angle, which first allowed intelligence to be converted into a type of measurable characteristic, though one operating primarily at the level of species or groups. Over the next century and a half, a number of other physical features were also evaluated as stand-ins for direct determinations of degree of intelligence, with most physical anthropologists according particular significance to cranial capacity and brain weight. Elaborate programs of measuring hundreds of skulls were carried out throughout Europe and the United States, with the results frequently used to provide scientific sanction for common beliefs about the intellectual inferiority of certain groups, most especially Africans and women, on the basis of the greater proximity of their mean skull or brain sizes to those for the non-human primates. As more data were collected, however, extreme variations were found both within and between groups, rendering group-level rankings in the eyes of many largely meaningless. At the same time, the efforts of women in feminist movements and blacks in anti-slavery campaigns produced powerful denunciations of the entire project of creating hierarchies of intelligence based on physical characteristics.

At the level of individuals, until the latter part of the nineteenth century intelligence as a personal characteristic distinguishing one individual from another generated little systematic interest, save for medical concern with diagnosing the profoundly mentally deficient. Mental philosophy and the emerging discipline of ‘scientific’ psychology were preoccupied with the universal characteristics of human reason and, in the case of psychology, with the process of subjecting mental features to new laboratory techniques being imported from physiology. As the evolutionary theories of Charles Darwin and Herbert Spencer became more broadly accepted, however, interest grew in the overall mental power of an organism, because it was deemed to be a critical characteristic shaping the organism’s adaptation to its environment. Greater pressure to understand the nature of individual differences was also developing as the result of a number of institutional and social changes occurring throughout the West. The spread of universal primary education, the increase in urban concentrations of workers, and the expansion of factory methods of production, along with the rapid growth in asylums for the mentally deficient, all provided many more opportunities to engage in systematic comparisons at an individual level, and thus helped to make intellectual differences much more visible and socially meaningful.

2. Intelligence And Its Tests

During the late nineteenth century, a number of investigators began to explore the meaning of individual differences, including those associated with overall level of intelligence. In England, Francis Galton carried out an extensive program of quantifying human mental and physical characteristics (anthropometrics) toward the goal of identifying superior members of the human stock. His Hereditary Genius ( [1869], 1972) argued that innate differences in overall superiority existed within human groups, that those differences were mental in origin, and that they were inheritable. Galton’s work helped to initiate widespread enthusiasm for anthropometry, one that persisted until the end of the nineteenth century. It was also a basis for his promulgation of the science of eugenics, which conceived of human progress in biological terms and advocated improvement in the quality of the breeding stock through encouraging marriages and child bearing among the most ‘fit’ (i.e., most intelligent) and restricting them among the least.

On the other side of the English Channel, psychologist Alfred Binet, one of the pioneers in the development of psychologie individuelle in France, conducted a wide range of investigations at the turn of the twentieth century into the nature of human mental ability. As one of these projects, in collaboration with Theodore Simon, Binet developed the initial version of what would become the first successful individual intelligence assessment instrument, the Binet–Simon Intelligence Scale (1905), a group of age-related tasks whose purpose was to reveal whether an examinee’s overall intelligence was developing at a ‘normal’ rate. The measuring aspect of the scale was enhanced following its 1908 and 1911 revisions, when results from the testing were reported in terms of mental age (MA), which facilitated conceiving of intelligence as a physical and quantifiable object.

Binet’s death soon after the publication of the 1911 scale robbed the Binet–Simon of its most effective champion in France and interest in intelligence testing there soon waned. Such was not the case elsewhere in the West, however, most especially in the United States. With the help of American psychologist Henry Herbert Goddard, who introduced the 1908 version of the scale to his fellow US psychologists in 1910, the Binet–Simon was adopted with enthusiasm. Rival versions of the test were soon produced in great numbers and a vogue for testing developed that never completely vanished.

Stanford University psychologist Lewis M. Terman’s 1916 revision of the scale, his Stanford–Binet (Terman 1916), did much to cement the place of intelligence testing within the American intellectual and cultural landscape. Thoroughly overhauled for an American population, the Stanford–Binet provided clearer age demarcations and popularized a new way of quantifying mental ability, the Intelligence Quotient (IQ), a ratio of mental age to chronological age (times 100) designed to remain constant over time. Terman celebrated this feature of IQ, argued that it provided a measure of an individual’s innate mental ability and suggested that a range of social decisions, including the nature of the occupation an individual should take up and whether or not he/she should be institutionalized, could be made on the basis of this number.

While not every mental tester was as certain about the implications of IQ as Terman, during the 1920s use of intelligence tests in a variety of contexts spread widely, facilitated by the creation of a group mental test for the World War I war effort that allowed 1.75 million US army recruits to be assessed without needing the time-consuming one-on-one methods of the Stanford–Binet. Terman’s individual scale, revised in 1937 and 1960, however, remained the gold standard for measurements of intelligence, though its preeminence began to be challenged starting in the 1940s with the creation by David Wechsler of the Wechsler Intelligence Scale for Children (WISC) and the Wechsler Adult Intelligence Scale (WAIS), instruments that generate assessments of verbal and non-verbal intelligence as well as an IQ.

3. The Nature Of Intelligence

Concomitant with the rise of intelligence testing came a series of debates over the characteristics of the object being measured. In 1904, British psychologist Charles Spearman used early test data to argue for the unitary nature of intelligence, explaining performance on mental tests in terms of general intelligence (g) and specific abilities (s). While numerous researchers— including Karl Pearson, Goddard, and Terman— accepted his analysis, others were skeptical, insisting instead that intelligence was composed of a number of primary independent abilities. Edward L. Thorndike in the United States was among the first to articulate this position, and he was soon joined during the 1920s by two statistically sophisticated psychologists, L. L. Thurstone in the US and Godfrey Thomson in the UK. In the period after World War II, psychologists continued to put forward a range of interpretations of the composition of intelligence: while Hans Eysenk remained convinced of the reality of g, for example, Philip E. Vernon proposed a hierarchical model of intelligence that inter-linked specific skills, general abilities, and overall intelligence, and Joy P. Guilford contended that intelligence was composed of as many as 150 independent factors. Later influential additions to these models included Howard Gardner’s theory of the existence of seven discrete types of intelligence and Robert J. Sternberg’s triarchic conception of intelligence.

Overshadowing all of the arguments over intelligence, however, has undoubtedly been the nature– nurture question. Figures such as Galton, Spearman, Pearson, and Terman argued early in the twentieth century strenuously for the nature position, with Galton producing studies on identical twins that have served as a model for investigations into the relative weights of heredity and environment. During the 1900s to 1930s, when eugenics was at the apex of its popularity, arguments in favor of intelligence as an inheritable biological entity ran strong and were used to justify calls for immigration restriction and for the sterilization of the mentally ‘unfit,’ as well as for the creation of multi-tracked secondary schools. At the same time, however, anthropologists were beginning to put renewed emphasis on culture as the primary determinant of human behavior, claims strengthened during the middle of the twentieth century by studies carried out especially at the Iowa Child Welfare Research Station, where IQ was found to change depending on nutrition and educational environment. The post-war period continued to see the debate pressed from both sides, with increasingly sophisticated twin studies showing high IQ correlations between identical twins separated at birth, while at the same time other researchers were teasing out ever more complicated connections between intelligence development and such factors as nutrition, family child-rearing practices, socio-economic status, and quality of education received.

While few experts would deny the influence of both genes and environment, the vociferous debate in the mid-1990s over The Bell Cur e (Herrnstein and Murray 1994), with its claims that IQ is hereditary and a prime determinant of an individual’s future, indicates that broad disagreements persist about intelligence and show little likelihood of quick resolution. What they reveal as well is that the language of native intelligence has remained a powerful vehicle for discussions of a range of social issues, from the organization of the educational system to the value of affirmative action programs to the just allocation of social resources.

Bibliography:

1. Danziger K 1997 Naming the Mind: How Psychology Found its Language. Sage, London
2. Degler C N 1991 In Search of Human Nature: The Decline and Re i al of Darwinism in American Social Thought. Oxford University Press, New York
3. Galton F [1869] 1972 Hereditary Genius: An Inquiry into Its Laws and Consequences. Peter Smith, Gloucester, USA
4. Gould S J 1981 The Mismeasure of Man. Norton, New York
5. Herrnstein R J, Murray C 1994 The Bell Cur e: Intelligence and Class Structure in American Life. Free Press, New York
6. Rose N 1985 The Psychological Complex: Psychology, Politics and Society in England, 1869–1939. Routledge & Kegan Paul, London
7. Smith R 1997 The Norton History of the Human Sciences. Norton, New York
8. Sutherland G 1984 Ability, Merit and Measurement. Oxford University Press, Oxford, UK
9. Terman L M 1916 The Measurement of Intelligence: An Explanation of and a Complete Guide for the Use of the Stanford Revision and Extension of the Binet–Simon Intelligence Scale. Houghton Mifflin, Boston
10. Zenderland L 1998 Measuring Minds: Henry Herbert Goddard and the Origins of American Mental Testing. Cambridge University Press, Cambridge, UK