Psychologists debate: Should we consider intelligence as one aptitude or many? As linked to cognitive speed? As neurologically measurable? On this much, intelligence experts agree: Intelligence is a concept and not a “thing.”
In many research studies, intelligence has been operationally defined as whatever intelligence tests measure, which has tended to be school smarts. But intelligence is not a quality like height or weight, which has the same meaning to everyone around the globe. People assign the tern! intelligence to the qualities that enable success in their own time and in their own culture (Sternberg & Kaufman, 1998). In the Amazon rain forest, intelligence may be understanding the medicinal qualities of local plants. In a North American high school, it may be mastering difficult concepts in tough courses. In both locations, intelligence is the ability to learn from experience, solve problems, and use knowledge to adapt to new situations. An intelligence test assesses people’s mental abilities and compares them with others, using numerical scores.
You probably know some people with talents in science, others who excel in social studies, and still others gifted in athletics, art, music, or dance. You may also know a talented artist who is stumped by the simplest math problem, or a brilliant math student with little aptitude for literary discussion. Are all these people intelligent? Could you rate their intelligence on a single scale? Or would you need several different scales?
Charles Spearman (1863-1945) believed we have one general intelligence (often shortened to g). He granted that people often have special abilities that stand out and he helped develop factor analysis, a statistical procedure that identifies clusters of related items. But Spearman also found that those who score high in one area, such as verbal intelligence, typically score higher than average in other areas, such as spatial or reasoning ability, Spearman believed a common skill set, the g factor, underlies all intelligent behavior, from navigating the sea to excelling in school.
This idea of a general mental capacity expressed by a single intelligence score was controversial in Spearman’s day, and so it remains. One of Spearman’s early opponents was L. L. Thurstone (1887-1955). Thurstone gave 56 different tests to people and mathematically identified seven clusters of primary /mental abilities (word fluency, verbal comprehension, spatial ability, perceptual speed, numerical ~ ability, inductive reasoning, and memory). Thurstone did not rank people on a single scale of general aptitude, 1 But when other investigators studied these profiles, they detected a persistent tendency: Those who excelled in one of the seven clusters generally scored well on the others. So, the investigators concluded, there was still some evidence of a g factor.
We might, then, liken mental abilities to physical abilities. Athleticism is not one thing but many. The ability to run fast is distinct from the eye-hand coordination required to throw a ball on target. A champion weightlifter rarely has the potential to be a skilled ice skater. Yet there remains some tendency for good things to come packaged together – for running speed and throwing accuracy to correlate, thanks to general athletic ability. So, too, with intelligence. Several distinct abilities tend to cluster together and to correlate enough to define a general intelligence factor.
Satoshi Kanazawa (2004, 2010) argues that general intelligence evolved as a form of intelligence that helps people solve novel problems-how to stop a fire from spreading, how to find food during a drought, how to reunite with one’s tribe on the other side of a flooded river. More common problems-such as how to mate or how to read a stranger’s face or how to find your way back to camp-require a different sort of intelligence. Kanazawa asserts that general intelligence scores do correlate with the ability to solve various novel problems (like those found in academic and many vocational situations) but do not much correlate with individuals’skills in evolutionarily familiar situations-such as marrying and parenting, forming close friendships, and navigating without maps. No wonder academic and social skills may come in different bodies.
Since the mid-1980s, some psychologists have sought to extend the definition of intelligence beyond Spearman’s and Thurstone’s academic smarts.
Howard Gardner (1983, 2006) views intelligence as multiple abilities that come in different packages. Brain damage, for example, may destroy one ability but leave others intact. And consider people with savant syndrome, who often score low on intelligence tests but have an island of brilliance (Treffert & Wallace, 2002). Some have virtually no language ability, yet are able to compute numbers as quickly and accurately as an electronic calculator, or identify the day of the week corresponding to any given historical date, or render incredible works of art or musical performance (Miller, 1999). About 4 in 5 people with savant syndrome are males, and many also have autism spectrum disorder (ASD; see Module 47).
The late memory whiz Kim Peek, a savant who did not have ASD, was the inspiration for the movie Rain Man. In 8 to 10 seconds, he could read and remember a page. During his lifetime, he memorized 9000 books, including Shakespeare and the Bible. He learned maps from the front of phone books and could provide GPS-like travel directions within any major U.S. city. Yet he could not button his clothes. And he had little capacity for abstract concepts. Asked by his father at a restaurant to “lower your voice,” he slid lower in his chair to lower his voice box. Asked for Lincoln’s Gettysburg Address, he responded, “227 North West Front Street. But he only stayed there one night – he gave the speech the next day” (Treffert & Christensen, 2005).
Using such evidence, Gardner argues that we do not have an intelligence, but rather multiple intelligences (FIGURE 60.1 on the next page), including the verbal and mathematical aptitudes assessed by standard tests. Thus, the computer programmer, the poet, the street-smart adolescent who becomes a crafty executive, and the basketball team’s point guard exhibit different kinds of intelligence (Gardner, 1998a).
Wouldn’t it be nice if the world were so just that being weak in one area would be compensated by genius in another? Alas, say Gardner’s critics, the world is not just (Ferguson, 2009; Scarr, 1989). Recent research, using factor analysis, has confirmed that there is a general intelligence fac tor Oohnson et a1., 2008): g matters. It predicts performance on various complex tasks and in various jobs (Gottfredson, 2002a,b, 2003a,b; see also FIGURE 60.2) . Much as jumping ability is not a predictor of jumping performance when the bar is set a foot off the ground – but becomes a predictor when the bar is set higher – so extremely high cognitive ability scores predict exceptional attainments, such as doctoral degrees and publications (Kuncel & Hezlett, 2010) .
Even so, “success” is not a one-ingredient recipe. High intelligence may help you get into a good college and ultimately a desired profession, but it won’t make you successful once there. The recipe for success combines talent with grit: Those who become highly successful tend also to be conscientious, well-connected, and doggedly energetic. K. Anders Ericsson (2002, 2007; Ericsson et al., 2007) reports a 10-year rule: A common ingredient of expert performance in chess, dancing, sports, computer programming, music, and medicine is “about 10 years of intense, daily practice.” Various animal species, including bees, birds, and chimps, likewise require time and experience to acquire peak expertise in skills such as foraging (Helton, 2008). As with humans, animal performance therefore tends to peak near midlife.
Robert Sternberg (1985, 1999, 2003) agrees that there is more to success than traditional intelligence and also agrees with Gardner’s idea of multiple intelligences. But he proposes a triarchic theory of three, not eight, intelligences:
With support from the U.S. College Board® (which administers the Advanced Placement® Program as well as the widely used SAT Reasoning Test® to U.S. college and university applicants), Sternberg (2006, 2007, 2010) and a team of collaborators have developed new measures of creativity (such as thinking up a caption for an untitled cartoon) and practical thinking (such as figuring out how to move a large bed up a winding staircase). Their initial data indicate that these more comprehensive assessments improve prediction of American students’ first-year college grades, and they do so with reduced ethnic-group differences.
Although Gardner and Sternberg differ on specific points, they agree that multiple abilities can contribute to life success. They also agree that the differing varieties of giftedness add spice to life and challenges for education. Under their influence, many teachers have been trained to appreciate such variety and to apply multiple intelligence theory in their classrooms.
Also distinct from academic intelligence is social intelligence – the know-how involved in successfully comprehending social situations. People with high social intelligence can read social situations the way a skilled football player reads the defense or a seafarer reads the weather. The concept was first proposed in 1920 by psychologist Edward Thorndike, who noted, “The best mechanic in a factory may fail as a foreman for lack of social intelligence” (Goleman, 2006, p. 83). Later psychologists have marveled that high-aptitude people are “not, by a wide margin, more effective ... in achieving better marriages, in successfully raising their children, and in achieving better mental and physical well-being” (Epstein & Meier, 1989). Others have explored the difficulty that some smart people have processing and managing social information (Cantor & Kihlstrom, 1987; Weis & Süss, 2007). This idea is especially significant for an aspect of social intelligence that John Mayer, Peter Salovey, and David Caruso (2002, 2008) have called emotional intelligence. They have developed a test that assesses four emotional intelligence components:
Mayer, Salovey, and Caruso caution against stretching “emotional intelligence” to include varied traits such as self-esteem and optimism. Rather, emotionally intelligent people are both socially and self-aware. And in both the United States and Germany, those scoring high on managing emotions enjoy higher-quality interactions with friends (Lopes et al., 2004). They avoid being hijacked by overwhelming depression, anxiety, or anger. Being sensitive to emotional cues, they know what to say to soothe a grieving friend, encourage a colleague, and manage a conflict.
Emotional intelligence is less a matter of conscious effort than of one’s unconscious processing of emotional information (Fiori, 2009).Yet the outgrowths of this automatic processing become visible. Across dozens of studies in many countries, those scoring high in emotional intelligence exhibit somewhat better job performance Goseph & Newman, 2010; Van Rooy & Viswesvaran, 2004; Zeidner et al., 2008). They also can delay gratification in pursuit of long-range rewards, rather than being overtaken by immediate impulses. They are emotionally in tune with others, and thus often succeed in career, marriage, and parenting situations where academically smarter (but emotionally less intelligent) people fail (Cherniss, 2010a,b; Ciarrochi et al., 2006).
Brain damage reports have provided extreme examples of the results of diminished emotional intelligence in people with high general intelligence. Neuroscientist Antonio Damasio (1994) tells of Elliot, who had a brain tumor removed: “I never saw a tinge of emotion in my many hours of conversation with him, no sadness, no impatience, no frustration.” Shown disturbing pictures of injured people, destroyed communities, and natural disasters, Elliot showed – and realized he felt – no emotion. He knew but he could not feel. Unable to intuitively adjust his behavior in response to others’ feelings, Elliot lost his job. He went bankrupt. His marriage collapsed. He remarried and divorced again. At last report, he was dependent on a disability check and custodial care from a sibling.
Some scholars, however, are concerned that emotional intelligence stretches the concept of intelligence too far. Multiple-intelligence man Howard Gardner (1999b) welcomes our stretching the concept into such realms as music and information about ourselves and others. But let us also, he says, respect emotional sensitivity, creativity, and motivation as important but different. Stretch “intelligence” to include everything we prize and it will lose its meaning.
You know it: You are smarter than some people and not as smart as others. Question: What in that heart of smarts – your brain – creates this difference? Is it your brain’s relative size? The amount of certain brain tissue? Your brain networks’ efficiency?
After the brilliant English poet Lord Byron died in 1824, doctors discovered that his brain was a massive 5 pounds, not the normal 3 pounds. Three years later, Beethoven died and his brain was found to have exceptionally numerous and deep convolutions. Such observations set brain scientists off studying the brains of other geniuses (Burrell, 2005). Do people with big brains have big smarts?
Alas, some geniuses had small brains, and some dim-witted criminals had brains like Byron’s. More recent studies that directly measure brain volume using MRI scans do reveal correlations of about +.33 between brain size (adjusted for body size) and intelligence score (Carey, 2007; McDaniel, 2005). Bigger is better.
One review of 37 brain-imaging studies revealed associations between intelligence and brain size and activity in specific areas, especially within the frontal and parietal lobes Gung & Haier, 2007; Tang et al., 2010). Intelligence is having ample gray matter (mostly neural cell bodies) plus ample white matter (axons) that make for efficient communication between brain centers (Deary et al., 2009; Haier et al., 2009).
Sandra Witelson would not have been surprised. With the brains of 91 Canadians as a comparison base, Witelson and her colleagues (1999) seized an opportunity to study Einstein’s brain. Although not notably heavier or larger in total size than the typical Canadian’s brain, Einstein’s brain was 15 percent larger in the parietal lobe’s lower region – which just happens to be a center for processing mathematical and spatial information.
The correlations between brain anatomy and intelligence only begin to explain intelligence differences. Searching for other explanations, neuroscientists are studying the brain’s functioning.
As people contemplate a variety of questions like those found on intelligence tests, a frontal lobe area just above the outer edge of the eyebrows becomes especially active – in the left brain for verbal questions, and on both sides for spatial questions (Duncan et al., 2000). Information from various brain areas seems to converge here, suggesting to researcher John Duncan (2000) that it may be a “global workspace for organizing and coordinating information” and that some people may be “blessed with a workspace that functions very, very well.”
Functioning well means functioning efficiently. Brain scans reveal that smart people use less energy to solve problems (Haier, 2009). They are like skilled athletes, for whom agile moves can seem effortless. Agile minds come with agile brains.
So, are more intelligent people literally more quick-witted, much as today’s speedier computer chips enable ever more powerful computing? On some tasks they seem to be. Verbal intelligence scores are predictable from the speed with which people retrieve information from memory (Hunt, 1983). Those who recognize quickly that sink and wink are different words, or that A and a share the same name, tend to score high in verbal ability. Extremely precocious 12- to 14-year-old college students are especially quick in responding to such tasks Gensen, 1989). To try to define quick-wittedness, researchers are taking a close look at speed of perception and speed of neural processing.
Across many studies, the correlation between intelligence score and the speed of taking in perceptual information tends to be about +.3 to +.5 (Deary & Der, 2005; Sheppard & Vernon, 2008). A typical experiment flashes an incomplete stimulus, as in FIGURE 60.3, then a masking image – another image that overrides the lingering afterimage of the incomplete stimulus. The researcher then asks participants whether the long side appeared on the right or left. Those whose brains require the least inspection time to register a simple stimulus tend to score somewhat higher on intelligence tests (Caryl, 1994; Deary & Caryl, 1993; Reed & Jensen, 1992).
Perhaps people who process more quickly accumulate more information. Or perhaps, as one Australian-Dutch research team has found, processing speed and intelligence correlate not because one causes the other but because they share an underlying genetic influence (Luciano et al., 2005).
***
For a summary of Spearman’s, Thurstone’s, Gardner’s, and Sternberg’s theories, see TABLE 60.1.