Intelligence.

A creative person is usually very intelligent in the ordinary sense of the term and can meet the problems of life as rationally as anyone can, but often he refuses to let intellect rule; he relies strongly on intuition, and he respects the irrational in himself and others. Above a certain level, intelligence seems to have little correlation with creativity--i.e., a highly intelligent person may not be as highly creative. A distinction is sometimes made between convergent thinking, the analytic reasoning measured by intelligence tests, and divergent thinking, a richness of ideas and originality of thinking. Both seem necessary to creative performance, although in different degrees according to the task or occupation (a mathematician may exhibit more convergent than divergent thinking and an artist the reverse).

Personality.

Many creative people show a strong interest in apparent disorder, contradiction, and imbalance; they often seem to consider asymmetry and disorder a challenge. At times creative persons give an impression of psychological imbalance, but immature personality traits may be an extension of a generalized receptivity to a wider-than-normal range of experience and behaviour patterns. Such individuals may possess an exceptionally deep, broad, and flexible awareness of themselves.

Studies indicate that the creative person is nonetheless an intellectual leader with a great sensitivity to problems. He exhibits a high degree of self-assurance and autonomy. He is dominant and is relatively free of internal restraints and inhibitions. He has a considerable range of intellectual interests and shows a strong preference for complexity and challenge.

The unconventionality of thought that is sometimes found in creative persons may be in part a resistance to acculturation, which is seen as demanding surrender of one's personal, unique, fundamental nature. This may result in a rejection of conventional morality, though certainly not in any abatement of the moral attitude.

Theories of intelligence

Theories of intelligence, as is the case with most scientific theories, have evolved through a succession of paradigms that have been put forward to clarify our understanding of the idea. The major paradigms have been those of psychological measurement (often called psychometrics); cognitive psychology, which concerns itself with the mental processes by which the mind functions; the merger of cognitive psychology with contextualism (the interaction of the environment and processes of the mind); and biologic science, which considers the neural bases of intelligence.

Psychometric theories

Psychometric theories have generally sought to understand the structure of intelligence: What form does it take, and what are its parts, if any? Such theories have generally been based on and tested by the use of data obtained from paper-and-pencil tests of mental abilities that include analogies (e.g., lawyer : client :: doctor : ?), classifications (e.g., Which word does not belong with the others? robin, sparrow, chicken, bluejay), and series completions (e.g., What number comes next in the following series? 3, 6, 10, 15, 21, ?).

Underlying the psychometric theories is a psychological model according to which intelligence is a composite of abilities measured by mental tests. This model is often quantified by assuming that each test score is a weighted linear composite of scores on the underlying abilities. For example, performance on a number-series test might be a weighted composite of number, reasoning, and possibly memory abilities for a complex series. Because the mathematical model is additive, it assumes that less of one ability can be compensated for by more of another ability in test performance. For instance, two people could gain equivalent scores on a number-series test if a deficiency in number ability in the one person relative to the other was compensated for by superiority in reasoning ability.

The first of the major psychometric theories was that of the British psychologist Charles E. Spearman, who published his first major article on intelligence in 1904. Spearman noticed what, at the turn of the century, seemed like a peculiar fact: People who did well on one mental ability test tended to do well on the others, and people who did not do well on one of them also tended not to do well on the others. Spearman devised a technique for statistical analysis, which he called factor analysis, that examines patterns of individual differences in test scores and is said to provide an analysis of the underlying sources of these individual differences. Spearman's factor analyses of test data suggested to him that just two kinds of factors underlie all individual differences in test scores. The first and more important factor Spearman labeled the "general factor," or g, which is said to pervade performance on all tasks requiring intelligence. In other words, regardless of the task, if it requires intelligence, it requires g. The second factor is specifically related to each particular test. But what, exactly, is g? After all, calling something a general factor is not the same as understanding what it is. Spearman did not know exactly what the general factor might be, but he proposed in 1927 that it might be something he labeled "mental energy."

The American psychologist L.L. Thurstone disagreed not only with Spearman's theory but also with his isolation of a single factor of general intelligence. Thurstone argued that the appearance of just a single factor was an artifact of the way Spearman did his factor analysis and that if the analysis were done in a different and more appropriate way, seven factors would appear, which Thurstone referred to as the "primary mental abilities." The seven primary mental abilities identified by Thurstone were verbal comprehension (as involved in the knowledge of vocabulary and in reading); verbal fluency (as involved in writing and in producing words); number (as involved in solving fairly simple numerical computation and arithmetical reasoning problems); spatial visualization (as involved in mentally visualizing and manipulating objects, as is required to fit a set of suitcases into an automobile trunk); inductive reasoning (as involved in completing a number series or in predicting the future based upon past experience); memory (as involved in remembering people's names or faces); and perceptual speed (as involved in rapidly proofreading to discover typographical errors in a typed text).

It is a possibility, of course, that Spearman was right and Thurstone was wrong, or vice versa. Other psychologists, however, such as the Canadian Philip E. Vernon and the American Raymond B. Cattell, suggested another possibility--that both were right in some sense. In the view of Vernon and Cattell, abilities are hierarchical. At the top of the hierarchy is g, or general ability. But below g in the hierarchy are successive levels of gradually narrowing abilities, ending with Spearman's specific abilities. Cattell, for example, suggested in a 1971 work that general ability can be subdivided into two further kinds of abilities, fluid and crystallized. Fluid abilities are the reasoning and problem-solving abilities measured by tests such as the analogies, classifications, and series completions described above. Crystallized abilities can be said to derive from fluid abilities and be viewed as their products, which would include vocabulary, general information, and knowledge about specific fields. John L. Horn, an American psychologist, suggested that crystallized ability more or less increases over the life span, whereas fluid ability increases in the earlier years and decreases in the later ones.

Most psychologists agreed that a broader subdivision of abilities was needed than was provided by Spearman, but not all of these agreed that the subdivision should be hierarchical. J.P. Guilford, an American psychologist, proposed a structure-of-intellect theory, which in its earlier versions postulated 120 abilities. For example, in an influential 1967 work Guilford argued that abilities can be divided into five kinds of operations, four kinds of contents, and six kinds of products. These various facets of intelligence combine multiplicatively, for a total of 5 4 6, or 120 separate abilities. An example of such an ability would be cognition (operation) of semantic (content) relations (product), which would be involved in recognizing the relation between lawyer and client in the analogy problem, lawyer : client :: doctor : ?. In 1984 Guilford increased the number of abilities proposed by his theory, raising the total to 150.

It had become apparent that there were serious problems with psychometric theories, not just individually but as a basic approach to the question. For one thing, the number of abilities seemed to be getting out of hand. A movement that had started by postulating one important ability had come, in one of its major manifestations, to postulating 150. Because parsimony is usually regarded as one of several desirable features of a scientific theory, this number caused some disturbance. For another thing, the psychometricians, as practitioners of factor analysis were called, didn't seem to have any strong scientific means of resolving their differences. Any method that could support so many theories seemed somewhat suspect, at least in the use to which it was being put. Most significant, however, was the seeming inability of psychometric theories to say anything substantial about the processes underlying intelligence. It is one thing to discuss "general ability" or "fluid ability," but quite another to describe just what is happening in people's minds when they are exercising the ability in question. The cognitive psychologists proposed a solution to these problems, which was to study directly the mental processes underlying intelligence and, perhaps, relate them to the factors of intelligence proposed by the psychometricians.

Cognitive theories

During the era of psychometric theories, the study of intelligence was dominated by those investigating individual differences in people's test scores. In an address to the American Psychological Association in 1957, the American psychologist Lee Cronbach, a leader in the testing field, decried the fact that some psychologists study individual differences and others study commonalities in human behaviour but never do the two meet. In Cronbach's address his plea to unite the "two disciplines of scientific psychology" led, in part, to the development of cognitive theories of intelligence and of the underlying processes posited by these theories. Without an understanding of the processes underlying intelligence it is possible to come to misleading, if not wrong, conclusions when evaluating overall test scores or other assessments of performance. Suppose, for example, that a student does poorly on the type of verbal analogies questions commonly found on psychometric tests. A possible conclusion is that the student does not reason well. An equally plausible interpretation, however, is that the student does not understand the words or is unable to read them in the first place. A student seeing the analogy, audacious : pusillanimous :: mitigate : ?, might be unable to solve it because of a lack of reasoning ability, but a more likely possibility is that the student does not know the meanings of the words. A cognitive analysis enables the interpreter of the test score to determine both the degree to which the poor score is due to low reasoning ability and the degree to which it is a result of not understanding the words. It is important to distinguish between the two interpretations of the low score, because they have different implications for understanding the intelligence of the student. A student might be an excellent reasoner but have only a modest vocabulary, or vice versa.

Underlying most cognitive approaches to intelligence is the assumption that intelligence comprises a set of mental representations (e.g., propositions, images) of information and a set of processes that can operate on the mental representations. A more intelligent person is assumed to represent information better and, in general, to operate more quickly on these representations than does a less intelligent person. Researchers have sought to measure the speed of various types of thinking. Through mathematical modeling, they divide the overall time required to perform a task into the constituent times needed to execute each mental process. Usually, they assume that these processes are executed serially--one after another--and, hence, that the processing times are additive. But some investigators allow for partially or even completely parallel processing, in which case more than one process is assumed to be executed at the same time. Regardless of the type of model used, the fundamental unit of analysis is the same: a mental process acting upon a mental representation.

A number of cognitive theories of intelligence have evolved. Among them is that of the American psychologists Earl B. Hunt, Nancy Frost, and Clifford E. Lunneborg, who in 1973 showed one way in which psychometrics and cognitive modeling could be combined. Instead of starting with conventional psychometric tests, they began with tasks that experimental psychologists were using in their laboratories to study the basic phenomena of cognition, such as perception, learning, and memory. They showed that individual differences in these tasks, which had never before been taken seriously, were in fact related (although rather weakly) to patterns of individual differences in psychometric intelligence test scores. These results, they argued, showed that the basic cognitive processes might be the building blocks of intelligence.

Following is an example of the kind of task Hunt and his colleagues studied in their research. The experimental subject is shown a pair of letters, such as "A A," "A a," or "A b." The subject's task is to respond as quickly as possible to one of two questions: "Are the two letters the same physically?" or "Are the two letters the same only in name?" In the first pair the letters are the same physically, and in the second pair the letters are the same only in name.

The psychologists hypothesized that a critical ability underlying intelligence is that of rapidly retrieving lexical information, such as letter names, from memory. Hence, they were interested in the time needed to react to the question about letter names. They subtracted the reaction time to the question about physical match from the reaction time to the question about name match in order to isolate and set aside the time required for sheer speed of reading letters and pushing buttons on a computer. The critical finding was that the score differences seemed to predict psychometric test scores, especially those on tests of verbal ability, such as verbal analogies and reading comprehension. The testing group concluded that verbally facile people are those who have the underlying ability to absorb and then retrieve from memory large amounts of verbal information in short amounts of time. The time factor was the significant development here.

A few years later, the American psychologist Robert J. Sternberg suggested an alternative approach to studying the cognitive processes underlying human intelligence. He argued that Hunt and his colleagues had found only a weak relation between basic cognitive tasks and psychometric test scores because the tasks they were using were at too low a level. Although low-level cognitive processes may be involved in intelligence, according to Sternberg they are peripheral rather than central. He proposed that psychologists should study the tasks found on the intelligence tests and then determine the mental processes and strategies that people use to perform those tasks.

Sternberg began his study with the analogies tasks such as lawyer : client :: doctor : ?. He determined that the solution to such analogies requires a set of component cognitive processes: namely, encoding of the analogy terms (e.g., retrieving from memory attributes of the terms lawyer, client, and so on), inferring the relation between the first two terms of the analogy (e.g., figuring out that a lawyer provides professional services to a client), mapping this relation to the second half of the analogy (e.g., figuring out that both a lawyer and a doctor provide professional services), applying this relation to generate a completion (e.g., realizing that the person to whom a doctor provides professional services is a patient), and then responding. Using techniques of mathematical modeling applied to reaction-time data, Sternberg proceeded to isolate the components of information processing. He determined whether or not each experimental subject did, indeed, use these processes, how the processes were combined, how long each process took, and how susceptible each process was to error. Sternberg later showed that the same cognitive processes are involved in a wide variety of intellectual tasks, and he suggested that these and other related processes underlie scores on intelligence tests.

Other cognitive psychologists have pursued different paths in the study of human intelligence, including the building of computer models of human cognition. Two leaders in this field have been the American psychologists Allen Newell and Herbert A. Simon. In the late 1950s and early 1960s they worked with a computer expert, Clifford Shaw, to construct a computer model of human problem solving. Called the General Problem Solver, it could solve a wide range of fairly structured problems, such as logical proofs and mathematical word problems. Their program relied heavily on a heuristic procedure called "means-ends analysis," which, at each step of problem solving, determined how close the program was to a solution and then tried to find a way to bring the program closer to where it needed to be. In 1972, Newell and Simon proposed a general theory of problem solving, much of which was implemented on the computer.

Most of the problems studied by Newell and Simon were fairly well structured, in that it was possible to identify a discrete set of moves that would lead from the beginning to the end of a problem. For example, in logical-theorem proving the final result is known, and what is needed is a discrete set of steps that lead to that solution. Even in chess, another object of study, a discrete set of moves can be determined that will lead from the beginning of a game to checkmate. The biggest problem for a computer program (or a human player, for that matter) is in deciding which of myriad possible moves will most contribute toward winning a game. Other investigators have been concerned with less well-structured problems, such as how a text is comprehended, or how people are reminded of things they already know when reading a text.

All of the cognitive theories described so far have in common their primary reliance on what psychologists call the serial processing of information. Fundamentally, this means that cognitive processes are executed in series, one after another. In solving an algebra problem, for example, first the problem is studied, then an attempt is made to formulate some equations to define knowns and unknowns, then the equations may be used to solve for the unknowns, and so on. The assumption is that people process chunks of information one at a time, seeking to combine the processes used into an overall strategy for solving a problem.

For many years, various psychologists have challenged the idea that cognitive processing is primarily serial. They have suggested that cognitive processing is primarily parallel, meaning that humans actually process large amounts of information simultaneously. It has long been known that the brain works in such a way, and it seems reasonable that cognitive models should reflect this reality. It proved, however, to be difficult to distinguish between serial and parallel models of information processing, just as it had been difficult earlier to distinguish between different factor models of human intelligence. Subsequently advanced techniques of mathematical and computer modeling were brought to bear on this problem, and various researchers, including the American psychologists David E. Rumelhart and Jay L. McClelland, proposed what they call "parallel distributed processing" models of the mind. These models postulated that many types of information processing occur at once, rather than just one at a time.

Even with computer modeling, some major problems regarding the nature of intelligence remain. For example, a number of psychologists, such as the American Michael E. Cole, have argued that cognitive processing does not take into account that the description of intelligence may differ from one culture to another and may even differ from one group to another within a culture. Moreover, even within the mainstream cultures of North America and Europe, it had become well known that conventional tests, even though they may predict academic performance, do not reliably predict performance in jobs or other life situations beyond school. It seemed, therefore, that not only cognition but also the context in which cognition operates had to be taken into account.

Contents of this article:

Introduction
Cognitive-contextual theories and biologic theories
Hemispheric studies
Development of intelligence
Post-Piaget theories and the environmental viewpoint
Measuring intelligence
The distribution of IQ scores and the malleability of intelligence