What is Intelligence and Can It Be Measured?
We might think of intelligence as the capacity for learning, reasoning, understanding and/or aptitude in grasping truths, relationships, facts, meanings, as described in at Does intelligence include metacognition and the executive processes of monitoring one's thinking? Many psychologists think so. But, psychologists disagree about whether intelligence is a single ability or many separate abilities (Woolfolk, 2005). The idea that intelligence is a basic ability comes from many studies confirming high positive correlations among tests designed to measure intellectual abilities. Such a theory results in the idea of a general intelligence as a single ability.
Another idea of intelligence is that of fluid and crystallized intelligence. Other theorists view intelligence as many separate abilities, rather than a single or pair of related abilities. Such theories include Gardner's theory of multiple intelligences and Sternberg's Triarchic Theory of Intelligence. While Gardner's multiple intelligence theory has been embraced or accepted by many educators, it has not received the same type of acceptance in the scientific community because such critics believe that what Gardner terms "intelligences" are really just talents or personality traits (Woolfolk, 2005). Indeed, with respect to the application of multiple intelligences to schooling, Gardner is not fond of the linkage between multiple intelligences and learning styles. Indeed, he doesn't believe that learners have consistent learning styles, nor does he deny the existence of general intelligence (Woolfolk, 2005). In fact, Gardner suggests that the theory has been misused by schools in some instances. For example, trying to include all intelligences in every lesson is rarely appropriate. For Gardner, one of the most important things with respect to the application of multiple intelligences in education is that teachers should approach a concept, subject matter, or a discipline in a variety of ways (specifically, schools should spend significant time on "essential questions"). Gardner believes that schools try to cover too much.
Intelligence is most often measured by standard tests, such as the Stanford-Binet test or the Wechsler Intelligence Scale for Children (WISC). One reason for this is because intelligence, as measured by these tests, is related (in terms of correlations) to learning in school. In fact, these tests grew out of tests developed to predict achievement in school….they were not originally developed as measures of “intelligence”.
It is important to note that individual differences with respect to learning are not limited to differences in intelligence. There are other individual differences that are describe different ways that people perceive and/or organize information (cognitive styles, for example, field-dependence vs. field independence and impulsive vs. reflective), how they approach learning (learning styles such as deep and surface approaches to processing information), and preferred ways of studying and learning (learning preferences, such as where, when, with whom, with what - such as background music, etc. - one likes to learn). However, and very importantly, there is not much research that supports the idea that assessing a children's learning styles and matching instruction to those styles has any effect on learning (Woolfolk, 2005). And, in fact, children may not be the best judges of how they should learn, so in fact the idea that they learn best when multitasking, for example, might be quite false.
The Nature of Intelligence: An Historical Perspective (19th and early 20th centuries)
Sir Francis Galton
Early concepts of intelligence focused on sensorimotoractivity. Sir Francis Galton, considered to be the father of the testing movement, conceptualized intelligence based on the philosophy of John Locke, that since our knowledge of the environment reaches us through the senses, that those with more acute sensory processes should be more intelligent. He therefore created tests of sensory discrimination and motor coordination to assess mental function.
Mental Inheritance. Galton sought to demonstrate that a person’s natural abilities are derived by inheritance, just as physical features are. His cousin, by the way, was Charles Darwin.
Galton posited that human abilities are genetically determined and the human species can be improved through controlled breeding practices, ushering in the wave of Eugenics in the late 19th and early to mid-twentieth centuries. Not taking into account privilege and environmental factors, Galton set out to prove the inheritance of intelligence, by examining eminent people and showed that the probability of fame was correlated with having a famous relative
Anthropometric Lab. In Galton’s lab be measured visual and auditory acuity, a judgment of visual distance, breathing power, reaction times, color discrimination, the strength of a blow, and olfactory discrimination. In 6 years, measured over 9000 people, and he wanted to define the range of abilities in the British Empire. While his ideas were off-target, the methods were on target, and, in fact, the method of norming is still in use today
Cyril Burt
Burt proposed that intelligence is strictly inheritedand that no influence of teaching, training, or environmentcould mitigate this. Thus, he concluded, income levels are determined by intelligence, not environment. Unfortunately, it appears as though old Cyril manufactured much of his data. However, if you review his entry at the Human Intelligence website ( you can see the issues in controversy in intelligence, testing, and academia!
Emil Kraepelin
Kraepelin developed tests to measure mental functioning, including tests of perception, memory, motor functions, and attention. He asserted that one needed to examine an individual enough times toreduce chance variation
Blin & Damaye
Blin & Damaye developed a set of standardized questions ordered by apparent difficulty that they claimed could identify mental retardation.
Alfred Binet
At the same time Blin & Damaye were working, Binet, Victor Henri, and Theodore Simon were developing methods for the study of mental functions. Key to this study was to focus on higher mental processes. Alfred Binet was a member of the Societe Libre pour l’Etude Psychologiquede l’Enfant, comprised of school folks who were interested in the scientific study of education. Binet asked to be a member and then was elected President. He then proposed that the French government needed to create tests to differentiate those who could not benefit from normal education from those who would not (stupid vs. malicious).
- He stated that …[some] children, if considered educably retarded, should be grouped in special classes annexed to the regular school, or in a special establishment, and…that a special class for the educable be opened for the present in one of the Paris schools, as a demonstration.
- As a result of the recommendation a Commission was formed to study the matter; Binet was one of the Commissioners. In 1905 he authored, with Theodore Simon, the Binet Scales of Intelligence. This was the first practical test of intelligence developed to differentiate between ―normal children and those who required additional instructional resources. There were 30 tests, with items ordered in level of difficulty; the more tasks completed, the greater the assumed intelligence of the subject.
Binet’s assumptions about intelligence. Whatever intelligence is, it is something that shows a normal and fairly consistent course of average intelligenceand it is needed for success in school.These two points formed the basis for the Binet-Simon scales.
Binet’s views on hereditability. The scientific atmosphere of the time was dominated by Darwinism and the theory of evolution. Binet, however, felt that intelligence was modifiable.He proposed mental orthopedics to assist with this modification.
Binet worked methodically and desired to improve classification of students rather than define intelligence as a concept.
Henry Goddard
Goddard was the director of the Vineland Hospital. He encountered the 1908 Binet Scale, liked it, used it, and then developed a translation of the scaleand worked to popularize the scale. He wanted to use adaptations of the Binet scale to differentiate classes of mental retardation and facilitate treatment. Think about how Goddard completely reconceptualized Binet’s ideas about the purpose of the scale!
Lewis Terman
Terman was a professor at Stanford University and observed that the 1908 Binet had great practical and theoretical value. He also recognized the need for standardization since there was now a proliferation of Binet scales. He revised the Binet-Simon scale, later called the Stanford-Binet, which replaced all other tests of intelligence. Terman added additional tests to supplement those in the Binet-Simon test. He standardized the test on 2600 California childrenand adopted the concept of mental quotient(which originated with Wilhelm Stern of Germany, 1914). Terman provided the formal expressionMA/CA = MQ, also known as a Ratio IQ Score. Terman renamed this ratio Intelligence Quotient. Later in the 1920’s, the formula would be amended so that the quotient was multiplied by 100. MA/CA x 100 = IQ
The Influence of World War I
The testing of military recruits provided the first massive use of psychological tests. Yerkes (Psychological Testing Corps) and Terman (Stanford University) created the Army Alphaand Army Betatests. These tests were intended to help the Army, primarily through the elimination of ―feeble-minded recruits. They were designed to measure native ability rather than the results of school testing (Samelson, 1977, p. 276). Hundreds of psychologists and psychology grad students were recruited to help. Among them was David Wechsler (who later developed the Wechsler Intelligence Scales for Children – WISC). They realized early on that individual testing would be too time consuming, so they designed the Alpha and Beta to be group administered. Eventually, over 2,000,000 intelligence tests were administered. 8,000 men recommended for immediate dischargeand 19,000 men were assigned to labor or development battalions.
This experience engrained the psychological test in American psychology. Because of Alpha and Beta, the General Education Fund initiated a grant for the development of an intelligence test for children. The result was the National Test of Intelligence—given to approximately 7 million children during the 1920’s. Testing provided unity for the field of
Psychology.
After the war, psychology was mostly centered on the scientific findings from the military data. This fed into discussion about eugenics, race deterioration, democracy, and public education. These discussions also dealt with results pertaining to race and
Nationality. For example, Southern and Eastern Europeans were inferior in scores to Northern Europeans, and African Americans were inferior to Caucasians on these tests. The findings were eventually abandoned but the resulting prejudices are still rather strong today.
Defining Intelligence
It is difficult to define intelligence. Before discussing theories of intelligence, we need to know what intelligence is. Definitions of intelligence have occupied much time amongst theoreticians in the field.
Binet defined intelligence functionally, in terms of school success and level at which students performed (no intelligence quotient).
Boring (1923): Intelligence is nothing more than a measurable capacity…to do well in an intelligence test. Intelligence is what the tests test.
Hebb (1949) felt that intelligence was an equivocal term that each writer can define…to suit himself, and there is no sense in arguing over terminology
Wechsler (1939) felt that intelligence is a global capacity and defined intelligence as the aggregate or global capacity of the individual to act purposefully, to think rationally, and to deal effectively with his environment
Evidence for global nature of intelligence would be that individuals who are skilled in certain areas do not possess what would commonly be called high levels of general intelligence.Similarly, individuals may do poorly on one test but are adept at other areas, such as solving problems and adapting to complex life situations. Spearman would later take up this argument.
Some see intelligence as a set of abilities. Others (Thorndike) argued that intelligence is composed of several different abilities. Evidence for this perspective is similar to that used to support the general intelligence position: People do not function at the same level in all areas(e.g., school grades).
Gardner (1985)developed the theory of multiple intelligencesand asserted that
…it is important to remain open to the possibility that many—if not most—of these competencies do not lend themselves to measurement by standard verbal methods, which rely heavily on a blend of logical and linguistic abilities.(Gardner, p. x, in Reitan & Wolfson, 1992, p. 523)
Sternberg (1997): Theory of Successful Intelligence
successful intelligence is the ability to succeed in life according to your own definition of success within your sociocultural context by capitalizing on your strengths and correcting or compensating for your weaknesses–and doing this through a combination of analytical, creative and practical skills in order to adapt to, shape, and select environments (Sternberg, 2003, p. 5)
Emotional intelligence:
the ability to monitor one’s own and others’ feelings and emotions, to discriminate among them and to use this information to guide one’s thinking and actions (Salovey & Mayer, 1990, p. 189) the capacity to process emotional information accurately and efficiently, including that information relevant to the recognition, construction and regulation of emotion in oneself and others(Mayer & Salovey, 1995, p. 197)
Strengths and limitations of intelligence tests
Strengths
- Provides some insight into the talents of some individuals ( improves educational opportunities for gifted students by placing them in more stimulating programs).
- Provides standardized ways of comparing a child’s performance with that of other children of similar age.
- Provides a profile of cognitive strengths and weaknesses (cognitive processing)
- Predictors of scholastic achievement.
- Measures the effects of changes associated with special programs, treatments, training, and recovery from illness.
Limitations
- Provides only a limited understanding of intelligence.
- Used to classify children into stereotyped categories, thereby possibly limiting their freedom to choose fields of study.
- Knowledge of their IQ may inhibit children’s level of aspiration and affect their self-concept.
- Do not measure the processes underlying a child’s responses.
- Misused as measures of innate capacity.
- A single number quantifying IQ does not do justice to the multidimensional nature of intelligence.
- Limited in predicting non-test or nonacademic intellectual activity.
- Cannot capture the complexity and immediacy of real-life situations involving the use of intelligence.
- Samples only a select number of conditions under which intelligent behavior is revealed.
- Fails to give credit to unconventional, original, or novel responses.
- Reflects abilities valued by our culture, including verbal ability, concept formation, judgment, reasoning, memory, comprehension, and spatial ability, but only measure a part of a domain that reflects intelligent behavior.
- Tendency to over interpret the IQ and fail to focus on the whole child.