What is IQ? What is intelligence?
In science, the term intelligence typically refers to what we could call academic or cognitive intelligence. In their book on intelligence, professors Resing and Drenth answer the question ‘What is intelligence?’ using the following definition: “The whole of cognitive or intellectual abilities required to obtain knowledge, and to use that knowledge in a good way to solve problems that have a well described goal and structure.” In ordinary language, one could say that intelligence refers to how smart or clever you are.
The first intelligence tests used in the field of psychology
The scales designed by Binet and Simon were the first intelligent tests that became widely accepted at the beginning of the 20th century. The Alpha and Beta army tests, that were used in World war I to assess military personnel, became very popular. In recent years, the Wechsler scales are the most widely used instruments in the field of psychology for measuring intelligence. The designer of these tests, Wechsler, published his first scale in the 1930s. He used material from the Binet Alpha and Beta tests to make his test. An important feature of his test was, that when calculating the IQ, this test took age into account. In other words, in the computation of the IQ, an age-correction takes place. Because of this feature, the IQ stays constant over the life span.
The Intelligence Quotient (IQ)
IQ is an acronym for Intelligence Quotient. So what is IQ? The IQ is a measurement of your intelligence and is expressed in a number. A person’s IQ can be calculated by having the person take an intelligence test. The average IQ is 100. If you achieve a score higher than 100, you are smarter than the average person, and a lower score means you are (somewhat) less smart. An IQ tells you what your score is on a particular intelligence test, often compared to your age-group. The test has a mean score of 100 points and a standard deviation of 15 points. What does this standard deviation mean? It means that 68 percent of the population score an IQ within the interval 85–115. And that 95 percent of the population scores within the interval 70–130.
Most people have an intuitive notion of what intelligence is, and many words in the English language distinguish between different levels of intellectual skill: bright/dull, smart/stupid, clever/slow, and so on. Yet no universally accepted definition of intelligence exists, and people continue to debate what, exactly, it is. Fundamental questions remain: Is intelligence one general ability or several independent systems of abilities? Is intelligence a property of the brain, a characteristic of behavior, or a set of knowledge and skills?
The simplest definition proposed is that intelligence is whatever intelligence tests measure. But this definition does not characterize the ability well, and it has several problems. First, it is circular: The tests are assumed to verify the existence of intelligence, which in turn is measurable by the tests. Second, many different intelligence tests exist, and they do not all measure the same thing. In fact, the makers of the first intelligence tests did not begin with a precise idea of what they wanted to measure. Finally, the definition says very little about the specific nature of intelligence.
Whenever scientists are asked to define intelligence in terms of what causes it or what it actually is, almost every scientist comes up with a different definition. For example, in 1921 an academic journal asked 14 prominent psychologists and educators to define intelligence. The journal received 14 different definitions, although many experts emphasized the ability to learn from experience and the ability to adapt to one’s environment. In 1986 researchers repeated the experiment by asking 25 experts for their definition of intelligence. The researchers received many different definitions: general adaptability to new problems in life; ability to engage in abstract thinking; adjustment to the environment; capacity for knowledge and knowledge possessed; general capacity for independence, originality, and productiveness in thinking; capacity to acquire capacity; apprehension of relevant relationships; ability to judge, to understand, and to reason; deduction of relationships; and innate, general cognitive ability.
People in the general population have somewhat different conceptions of intelligence than do most experts. Laypersons and the popular press tend to emphasize cleverness, common sense, practical problem solving ability, verbal ability, and interest in learning. In addition, many people think social competence is an important component of intelligence.
Most intelligence researchers define intelligence as what is measured by intelligence tests, but some scholars argue that this definition is inadequate and that intelligence is whatever abilities are valued by one’s culture. According to this perspective, conceptions of intelligence vary from culture to culture. For example, North Americans often associate verbal and mathematical skills with intelligence, but some seafaring cultures in the islands of the South Pacific view spatial memory and navigational skills as markers of intelligence. Those who believe intelligence is culturally relative dispute the idea that any one test could fairly measure intelligence across different cultures. Others, however, view intelligence as a basic cognitive ability independent of culture.
In recent years, a number of theorists have argued that standard intelligence tests measure only a portion of the human abilities that could be considered aspects of intelligence. Other scholars believe that such tests accurately measure intelligence and that the lack of agreement on a definition of intelligence does not invalidate its measurement. In their view, intelligence is much like many scientific concepts that are accurately measured well before scientists understand what the measurement actually means. Gravity, temperature, and radiation are all examples of concepts that were measured before they were understood.