Intelligence Tests Notebook Page 19 Intelligence Tests
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Unit 5: Cognitive Psychology Intelligence Tests Notebook Page 19 Intelligence Tests Regardless of the intelligence theory, one must have a valid test with which to assess intelligence. Intelligence tests are designed to measure one’s intellectual ability by assigning a numerical value and comparing to others. The first intelligence test was created by Francis Galton. Galton, Inspired by Charles Darwin’s evolutionary theory, embarked on a quest to find the most intelligent, athletic, and competent humans. His purpose was motivated by more than just curiosity, as Galton was a founding member of the eugenics movement—a movement bent on improving the human gene pool. Galton was looking for super humans in the hopes of breeding—or, rather, encouraging the breeding—of the world’s most intelligent and capable people. Galton attempted to find superior human subjects in feats of mental and physical ability by testing 10,000 participants. While he had hoped to find ideal humans and encourage them to reproduce, no such humans were found as results were inconsistent. While we care little about his failure to find superhumans, we do care that he formed the concept of using a numerical test to measure intellectual ability. Alfred Binet Another step was taken towards the accurate assessment of intelligence by Alfred Binet in 1904. As France had, at the time, just begun its new compulsory education program, they encountered the difficulty of throwing together many children of the same age that had very different levels of education. Some had been tutored to read and write since a young age. Others, raised rurally, had reached their teens with no reading or mathematical ability due to a lack of formal education. The French commissioned Alfred Binet with the task of developing a method with which to assess the intelligence of this wide-range of intellectual ability. Binet theorized that each student developed in a linear fashion with individuals progressing in comprehension at different speeds. Using the fundamental idea of intelligence testing set by Francis Galton, Binet created a test that assessed the student’s mental age, which was, essentially, the average performance of people at a certain age. For example, at the chronological age of 7, most students can add numbers proficiently. If one is 10 years old, but they are only able to add simple numbers, then their mental age would 7 as the average seven-year-old can only add simple numbers. This is how the terminology of reading or math skills at ‘2nd-grade’ or ‘4th-grade’ level have come into use—it essentially means the person in question’s mental age (or academic ability) is the same as that of the average 2nd or 4th grader. Binet developed this test for the sole purpose of identifying a students mental development to close the gap and catch their mental age up to their chronological age—not to demean or label a student. In fact, Binet expressly feared labelling and quantifying humans for their ‘intellect’ and exclusively used the testing to aid those in need. Louis Leon Thurstone After Binet’s mental age concept and Terman’s Stanford-Binet Test had grown in popularity, Louis Leon Thurstone, in 1938, transformed the field of intelligence and intelligence testing. Thurstone openly criticized Spearman’s factor analysis method, devising a far more effective and accurate psychometric technique. In fact, the fundamentals set by Thurstone are still used today during the process of factor analysis. With his new psychometric approach, he used factor analysis to reduce intelligence to seven primary factors: word fluency, verbal comprehension, spatial ability (positioning and direction), perceptual speed (the speed at which one can perceive and understand information), numerical ability, inductive reasoning (ability to identify patterns and make inferences), and memory. In doing so, Thurstone provided a much more accurate set of intelligence factors, and noted that while Spearman’s theory was generally true, and that most people scored similarly in all categories, there was a minority of exceptions. The techniques devised by Thurstone would later be used by researchers such as Howard Gardener to offer alternatives--or at least nuanced revisions--to Spearman’s theory about a general factor of intelligence. Intelligence Quotient Test Expanding on Binet’s ideas in 1916, Lewis Terman of Stanford University looked for genetic explanation of Spearman’s general factor of intelligence. By combining the concepts of mental age, and utilizing the test-making and factor analysis practices pioneered by Spearman, Terman devised the Stanford-Binet intelligence quotient (IQ) test. This was a test that analyzed one’s mental age, divided it by their chronological age, and then multiplied by 100. For example, an 8-year-old with the mental age of a 10-year-old would score a 125, as 10/8 x 100 = 125. As such, a person of average intelligence would have a score of 100, as their mental and chronological ages were identical. Terman’s formula revolutionized intelligence testing and led to the discovery that populations in stable, affluent nations tend to increase in intelligence over time. This development is known as the Flynn Effect, which asserts that once states are stable, provide education, and are also affluent enough to afford ample nutrition to children, teens, and adults for proper brain development, one’s genetic potential for intelligence may be realized. While the Flynn Effect has begun to level off in Western and East Asian nations (affluent nations that have been stable, affluent, and well- educated for decades), the phenomenon is consistent in developing nations. Like Galton, however, Terman also had eugenic ambitions, noting the higher scores of Western and Northern Europeans. While we now know these abnormally-high scores were due to early economic, political and educational stability relative to the rest of the world, many felt that Western and Northern Europeans were intellectually and genetically superior. As a result, the United States began to limit non-Western and non-Northern European immigrants in the early 20th-century, hoping only to accept immigrants from ‘genetically-superior’ populations. David Wechsler and Aptitude Tests Another major critic of Spearman’s general factor of intelligence was David Wechsler. Wechsler asserted that Spearman’s g factor was too narrow, and, furthermore, that intelligence was more an effect than a cause. Wechsler believed one’s personality and willingness to engage with people, situations, and information impacted their intelligence. In 1955, he developed the Wechsler Adult Intelligence Scale based on a deviation quotient rather than a mental age. This was, essentially, a more accurate measure of one’s fluid intelligence, as opposed to the more crystallized mental age developed by Binet. Tests that measure one’s natural ability to process and act on information resulted in the early forms of aptitude tests--tests that predict a person’s future performance and capacity to learn. Whether or not the person pursues that learning is dependent on a host of factors from environment, to personality, to motivation, which is why Wechsler felt intelligence was more a effect than a cause. The Wechsler Adult Intelligence Scale (WAIS) utilizes both verbal and non-verbal methods that focus on four primary categories to assess overall and individual intelligence factors: verbal comprehension, perceptual organization, working memory, and processing speed. Tasks include finding patterns/similarities, aligning blocks similarly, defining or identifying words, memorizing lists, and noting the time and accuracy with which one can accomplish these tasks. While the original WAIS Test has been modified several times, it profoundly influenced intellectual testing. Since Wechsler, modern aptitude tests are geared towards assessing problem solving capability, current levels of intelligence, processing speed, accuracy, and inductive reasoning—all of which borrow from Wechsler’s focus on verbal and non-verbal methods and his four intelligence factors. Validity In order for tests to be accurate or usable, they must be scrupulously analyzed to determine their validity. To determine their validity, tests must accomplish three distinct goals—they must be standardized, reliable, and valid. For a test to be standardized, the results must be compared to a presented group or population. All participants must receive the same test or set of tests, and, rather than be scored simply on your test accuracy, one is scored relative to the scores of other participants of the same test. This is known as a percentile —a relative ranking out of 100 according to the values of a particular variable. Secondly, the test results must be reliable, meaning scores of half of test, a new test, or retests or the same test, must have the same or similar results within a given population. This means intelligence or skills are being measured accurately as the crystallized and fluid intelligence of participants should score consistently across multiple tests in the same population. Lastly, the test must be valid, meaning it must accurately measure what it is supposed to. For example, if one is testing intelligence (be it achievement or aptitude), it should accurately predict the future performance of student learners. Tests are often valid and accurate amongst large random populations, but as populations age and become more educated, they become less accurate. This is known as predictive validity – the diminishing ability of tests to measure future learning. This tends to fade with age when the populations narrow to already-educated and motivated individuals. For example, if one tests 100 highly-intelligent graduate students, even if they score low relative to the others as a percentile, they are likely not far behind their counterparts and still far ahead of the rest of the population. It’s like ranking professional athletes… sure some are better than others, but they’re still professional athletes—they’re far better than the average person! Test Changes Since the 1950s, contemporary psychometrics has strayed away from the emphasis of older intelligence tests that focus solely on analytical test questions and answers.