The Measurement of Adult Intelligence - Essay Example

Intelligence Intelligence can be visualised from umpteen aspects. "From the perspective of the casual observer, intelligence is the capability to act intelligently when dealing with everyday life. If envisaged from an adult's eyes, intelligence is a specific measurement of their ability to learn. While not actually knowing their IQ scores, many adults have vague recollections of being labeled as an 'average,' 'above average,' or 'below-average' student". (2006a) According to Wechsler David, "Intelligence is the aggregate or global capacity of the individual to act purposefully, to think rationally and to deal effectively with his environment". (Wechsler, 1944, p.4) Intelligence is considered to be global as it characterises the individual's behaviour as a whole; it is a combination of those elements or abilities, which, though not entirely independent, are qualitatively differentiable. "By measurement of these abilities, we ultimately evaluate intelligence. But intelligence is not identical with the mere sum of these abilities, however inclusive". (Wechsler, 1944, p. 6) Wechsler suggests that there are three important reasons, which justify this statement: (1) The ultimate products of intelligent behaviour are not only a function of the number of abilities or their quality but also of the way in which they are combined, that is, upon their configuration. (2) Factors other than intellectual ability, for example, those of drive and incentive, enter into intelligent behaviour. (3) Finally, while different orders of intelligent behaviour may require varying degrees of intellectual ability, an excess of any given ability may add relatively little to the effectiveness of the behaviour as a whole. It would seem that, so far as general intelligence is concerned, intellectual ability as such merely enters as a necessary minimum. "Thus, to act intelligently, one must be able to recall numerous items i.e., have a retentive memory. But beyond a certain point and age in developmental life span, this ability does not help much in coping with life situations successfully". (Wechsler, 1944, p. 6) If we consider intelligence in middle age, it is confirmed that adults aged between 30-50 are subjected to decline capabilities in divergent thinking. However the extent to which decline is confronted can be evaluated through various measurement tests and techniques. "Although intelligence is no mere sum of intellectual abilities, the only way we can evaluate it quantitatively is by the measurement of the various aspects of these abilities. There is no contradiction here unless we insist upon the identity of general intelligence and intellectual ability". (Wechsler, 1944, p. 8) Researchers have always related intelligence to different mental processes. More recently psychologists have began to emphasize not only the processes but the content as well. They speak of memory but of auditory memory; not only of reasoning but of abstract, verbal or arithmetical reasoning. In a like manner some psychologists have begun to distinguish various kinds of intelligence. Thorndike, has suggested subdividing intelligence into three main types: (1) Abstract or verbal intelligence, involving facility in the use of symbols; (2) Practical intelligence, involving facility in manipulating objects; (3) Social intelligence, involving facility in dealing with human beings. The significant thing about this classification is that it emphasises upon the age criteria, accomplishments a person can achieve and how he can do it. This distinction between function and content is fully justified by experimental evidence. The rating, which an individual attains on an intelligence examination, depends to a considerable degree on the type of test used. His score on a test made up largely of verbal items may differ significantly from that obtained on a test involving questions of social comprehension and still more from another test made up of items involving predominantly psychomotor reactions and the perception of spatial relationships. Adult Intelligence While evaluating adult intelligence the difficulty is most acutely apparent when intelligence levels are given in the now almost universal notation of mental age. "Most psychologists are aware of the fact that when an adult of 30 scores a mental age of 12, and a child of 12 scores a mental age of 12, their intelligence is not identical, yet there does not seem to be any general understanding as to why they are not identical. The basic reason a mental age of 12 at 12 does not mean the same thing as a mental age of 12 at 30, is that the measured abilities and hence the intelligence scores represent different portions of the subjects' respective total intelligence". (Wechsler, 1944. p. 48) Sufficient has been said to show that the definition of general intelligence, far from being a mere theoretical question, is one, which enters immediately into any practical attempt at measurement. It is particularly important when we come to measuring middle-aged adult intelligence, because we are at once confronted with a wider range of criteria against which our definition may be checked. Intelligence is often by most of the researchers considered to decline after 30s. The reason has been known for some time is that the mean weight of the adult brain declines with age. "The skull thickens and the brain shrinks. It we accept the brain as the organ of the mind; it is only reasonable to assume that even gross changes such as alterations of weight may also affect its function. Assuming that to be the case, we should expect that the changes in brain weight show some concomitance with alterations in general intellectual ability. The decline in the weight of brain, like that in intellectual ability, is essentially linear. After reaching a maximum, at about age 20, the brain begins to decline in weight, somewhat irregularly at first, but after 30 it starts declining at a fairly constant rate". (Wechsler, 1944, p. 40) If our generalizations regarding the influence of age on mental deterioration are correct, it follows that mental deterioration in human beings begins at a relatively early age. However, to speak of a person in his early 30's as showing signs of deterioration because he already manifests some measurable decline of ability, would be stretching the term beyond its usual connotation. Clearly that is not what is implied by deterioration in the ordinary sense. It would seem desirable to restrict the term to only such impairment or losses in ability as are significantly greater than those due to the age factor alone. To do this we must necessarily know what the normal loss of ability is for the average individual and the mean limits of variability at all ages for the normal population. But even with these facts at hand we are only at the beginning of our task. To evaluate deterioration we must be able to measure it quantitatively. Wechsley suggests the measurement of mental deterioration involves three separate problems: (1) The reliable measurement of the individual's actual or present functioning ability; (2) The evaluation of his previous functioning level; (3) The expression of the difference between the two in meaningful, quantitative terms. "Up to the present, none of the three problems has had complete solution. We say none, although as regards the measurement of present functioning ability this statement is not altogether correct. We do have considerable means of measuring an individual's functioning ability, but these means, in general, are unsuitable for precisely those groups on whom they are most needed in studying mental deterioration, namely, the older adults". (Wechsley, 1944, p. 52) According to Mackintosh research, "studies of adult jobholders, in Britain have consistently reported a significant correlation, of the order of 0.50-0.60 between their IQ scores and the status of their jobs. In one important longitudinal study, McCall (1977) showed that the IQ scores of children as young as 8 years old correlated over 0.40 with the status of their adult jobs when they were 40". (Mackintosh, 1998, p. 52) So, the evidence supports the fact that intelligence fluctuates and ultimately declines in the middle aged adults. Every human capacity after attaining a maximum begins an immediate decline. This decline is at first very slow but after a while increases perceptibly. The age at which the maximum is attained varies from ability to ability but seldom occurs beyond 30. Once the decline begins it progresses continually. Between the ages of 30 and 50 it is more or less linear. Fluid intelligence starts declining after attaining the age of 30. "Middle-aged adults possess the ability to apply mental powers to new problems, perceiving relationships, forming concepts and drawing inferences, however they also confront to the decline and utilisation of these abilities probably due to changes in brain". (2006b) References 2006a, accessed on July 25, 2006 from 2006b, Cantu Ethel, accessed form Mackintosh N. J., 1998. "IQ and Human Intelligence": Oxford University Press. Place of Publication: Oxford. Publication Wechsler David, 1944. "The Measurement of Adult Intelligence": Williams & Wilkins. Place of Publication: Baltimore, MD. Read More