Unlike other species, humans owe their success more to thinking abilities and intelligence than to physical strength or speed. That’s why our species is called Homo sapiens (from the Latin for man and wise). Our intelligence makes us highly adaptable creatures. We live in deserts, jungles, mountains, frenzied cities, placid retreats, and space stations.
Consider Stephen Hawking. He can’t walk or talk. When he was 13, Lou Gehrig’s disease began to slowly destroy nerve cells in his spinal cord, short-circuiting messages between his brain and muscles. Today, he is confined to a wheelchair and “speaks” by manually controlling a speech syn- thesizer. Yet, despite his severe disabilities, his brain is unaffected by the disease and remains fiercely active. He can still think. Stephen is a theoretical physicist and one of the best-known sci- entific minds of modern times. With courage and determination, he has used his intellect to advance our understanding of the universe.
What do we mean when we say that a person like Stephen Hawking is “smart” or “intelligent”? Can intelligence be measured? Can intelligence tests predict life success? What are the conse- quences of having extremely high or low intelligence? These questions and others concerning intelligence have fascinated psychologists for more than 100 years. Let’s see what has been learned and what issues are still debated.
Gateway QUESTIONS 9.1 How do psychologists define intelligence? 9.2 What are typical IQ tests like? 9.3 How do IQ scores relate to sex, age, and
occupation? 9.4 What does IQ tell us about genius?
9.5 What causes intellectual disability? 9.6 How do heredity and environment affect
intelligence? 9.7 Are there alternate views of intelligence? 9.8 Is there a downside to intelligence testing?
9781285519517, Introduction to Psychology: Gateways to Mind and Behavior with Concept Maps and Reviews, Thirteenth Edition, Coon/Mitterer – © Cengage Learning. All rights reserved. No distribution allowed without express authorization.
Defining Intelligence— Intelligence Is … You Know, It’s …
Gateway Question 9.1: How do psychologists define intelligence? Like many important concepts in psychology, intelligence cannot be observed directly. Nevertheless, we feel certain it exists. Let’s compare two children:
When she was 14 months old, Anne wrote her own name. She taught her- self to read at age 2. At age 5, she astounded her kindergarten teacher by bringing an iPad to class—on which she was reading an encyclopedia. At 10, she breezed through an entire high school algebra course in 12 hours.
Billy, who is 10 years old, can write his name and can count, but he has trouble with simple addition and subtraction problems and finds multipli- cation impossible. He has been held back in school twice and is still incapa- ble of doing the work his 8-year-old classmates find easy.
Anne is considered a genius; Billy, a slow learner. There seems little doubt that they differ in intelligence.
Wait! Anne’s ability is obvious, but how do we know that Billy isn’t just lazy? That’s the same question that Alfred Binet faced in 1904 (Benjafield, 2010; Jarvin & Sternberg, 2003). The French minister of education wanted to find a way to distinguish slower students from the more capable (or the capable but lazy). In a flash of bril- liance, Binet and an associate created a test made up of “intellec- tual” questions and problems. Next, they learned which questions an average child could answer at each age. By giving children the test, they could tell whether a child was performing up to his or her potential (Kaplan & Saccuzzo, 2009; Kaufman, 2000).
Binet’s approach gave rise to modern intelligence tests. At the same time, it launched an ongoing debate. Part of the debate is related to the basic difficulty of defining intelligence (Sternberg, Grigorenko, & Kidd, 2005).
Defining Intelligence Isn’t there an accepted definition of intelligence? Traditionally, yes. Intelligence is the global capacity to act purposefully, to think rationally, and to deal effectively with the environment (Wechsler, 1939). The core of intelligence is usually thought to consist of a small set of general mental abilities (called the g-factor) in the areas of reasoning, problem solving, knowledge, memory, and successful adaptation to one’s surroundings (Barber, 2010; Sternberg, 2004).
Intelligence has traditionally been considered a cognitive, not an emotional, capacity. Is there such a thing as emotional intelligence? To find out, see Chapter 10, pages 363–364.
Beyond this, however, there is much disagreement. In fact, many psychologists simply accept an operational definition of intelligence by spelling out the procedures they use to measure it (Neukrug & Fawcett, 2010). Thus, by selecting items for an intel- ligence test, a psychologist is saying in a very direct way, “This is
what I mean by intelligence.” A test that measures memory, reason- ing, and verbal fluency offers a very different definition of intelli- gence than one that measures strength of grip, shoe size, length of the nose, or the person’s best Guitar Hero score (Goldstein, 2011).
Aptitudes As a child, Hedda displayed an aptitude for art. Today, Hedda is a successful graphic artist. How does an aptitude like Hedda’s differ from general intelligence? An aptitude is a capacity for learning certain abilities. Persons with mechanical, artistic, or musical apti- tudes are likely to do well in careers involving mechanics, art, or music, respectively (• Figure 9.1).
Are there tests for aptitudes? How are they different from intelli- gence tests? Aptitude tests measure a narrower range of abilities than do intelligence tests (Kaplan & Saccuzzo, 2009). For example, special aptitude tests predict whether you will succeed in a single
RANGE OF ABILITIES
Multiple aptitude tests
Special aptitude tests
Modern intelligence tests are widely used to measure cognitive abilities. When properly administered, such tests provide an operational definition of intelligence.