Cover Story

Intelligence research takes place in almost every branch of psychology, though it doesn't always go by that name.

Recent advances have taken place in research on emotional intelligence, a popular idea that some researchers are struggling to keep grounded in science; stereotype threat, a phenomenon that may account for discrepancies in test scores among ethnic groups in the United States; and the genetics of intelligence, a research area with a controversial past that is poised to benefit from recent advances in neuroscience and genetics.

Emotional intelligence

A search for the phrase "emotional intelligence" (EI) on the Internet search engine Google turns up more than 100,000 documents. That's not much compared to "self-esteem" (1,130,000) or "IQ" (3,360,000), but it is striking for a psychological term that was introduced to the literature in 1990 and that was known only to a few specialists before 1995. The term's popularity can be attributed largely to a single event: the publication of the book "Emotional Intelligence" (Bantam Books, 1995) by Daniel Goleman, PhD, which sparked explosive growth in EI research in the late 1990s.

Since the book's publication, EI research has proceeded along two parallel streams. One of those streams has been based largely on Goleman's book. Its practitioners tend to take an inclusive view of EI, to use self-report or questionnaire-style measures, and to make strong claims about the importance of EI in schools and workplaces. The other stream has been based on the work of University of New Hampshire psychologist John Mayer, PhD, and Yale University psychologist Peter Salovey, PhD, whose research served as Goleman's original inspiration. Researchers in that stream have attempted to define EI as a kind of intelligence and to use measures that resemble traditional intelligence tests.

Recently, Gerald Matthews, PhD, Moshe Zeidner, PhD, and Richard D. Roberts, PhD, of the University of Sydney, attempted to sift through the voluminous research produced by both streams and to identify the field's strengths and weaknesses. The results of their research are described in a new book, "Emotional Intelligence: Science and Myth" (MIT Press, 2003).

Their conclusion: EI still has a long way to go. Self-report measures of EI, they argue, are often little more than reformulations of traditional personality scales; most theories of EI fail to take into account well-established theories about emotion and intelligence; and attempts to apply EI in schools and workplaces are often more hype than substance.

Mayer agrees that the quality of research on EI is mixed. "If you're going to take the term 'emotional intelligence' seriously as an intelligence," he says, "it's got to be about how one reasons about emotions and also about how emotions help reasoning, and most of the field does not do that."

But Mayer is optimistic about the future of EI. He and his collaborators recently published a new test of EI that appears to meet all of the psychometric criteria for a traditional intelligence test, he says. And as the field matures--with the help of criticisms such as those presented by Matthews, Zeidner and Roberts--Mayer says he expects to find further evidence that EI is a useful scientific construct.

Stereotype threat

Gaps between the average test performance of African-Americans and European Americans have proven to be remarkably persistent, remaining even when socioeconomic status, prior performance and other factors have been accounted for. That's one of the reasons why the research of Stanford University psychologist Claude Steele, PhD, and others on the effect of stereotypes on test performance has had such a large impact. The research offers an explanation--the cognitive and emotional burden of "stereotype threat"--for part of that gap, as well as for other kinds of performance differences between groups stereotyped on the basis of race, gender, age and other social distinctions.

But while Steele's work has spurred a number of other researchers to follow his lead, it has also encountered criticism. University of Minnesota psychologist Paul Sackett, PhD, for one, worries that the extent to which stereotype threat explains the testing gap has been exaggerated.

"It's clear that Steele shows a very interesting phenomenon in his lab," says Sackett. "It's provocative, it's well done, it's fascinating as all get-out. The question is, is it just a lab phenomenon or will it generalize to the real world?"

That question has yet to be answered definitively, although Steele says that numerous studies have demonstrated the importance of stereotype threat under real-world conditions. And several recent studies suggest that attempts to reduce the effects of stereotype threat in schools can improve student performance.

Of course, says Steele, many of the manipulations used in the laboratory--such as telling participants that a test is unimportant--can't be used in the real world. "In the real world, these tests are about abilities and, for the most part, they're taken by people who care about them," he says. "To get the threat out of the situation, you have to do something, like what we did, that you can't do in real life." But, he says, that does not mean that interventions that reduce stereotype threat or teach people how to minimize its negative effects can't work.

Some of the most interesting new research on stereotype threat suggests that the cues that trigger it can be pervasive and subtle, says Steele. In a study published last year in Personality and Social Psychology Bulletin (Vol. 28, No. 12), for instance, Stanford researcher Paul Davies, PhD, and his collaborators reported that television commercials that depict stereotypical female behavior impair women's performance on math tests and reduce their interest in pursuing quantitative careers.

A collection of research papers on stereotype threat, with commentary by Steele and Sackett, will appear in a special issue of the journal Human Performance this fall.

Genes and intelligence

In 1998, Robert Plomin, PhD, and his collaborators published a study suggesting that a variation in the gene for IGF-2R, a receptor for a human growth factor, was associated with extremely high SAT scores. The gene accounted for only a small amount of variance in scores--about 2 percent--but the finding suggested that scientists had taken a step toward explaining differences in intelligence in biological terms. As such, it made a huge splash in the media.

Last year, however, when Plomin and his collaborators published a follow-up study in Psychological Science (Vol. 13, No. 6) that failed to replicate the initial findings, the announcement caused barely a ripple.

The story illustrates both the difficulty of trying to link individual genes to intelligence--a complex behavioral trait that is likely to be influenced by dozens if not hundreds of genes, as well as the environment--and the complicated cultural landscape in which such research is conducted.

Despite that setback, Plomin, a professor of behavioral genetics at the Institute of Psychiatry in London, still believes that the evidence in favor of a genetic explanation for much of the variation in intelligence among individuals is strong. Studies on twins have suggested that most inherited differences in cognitive ability can be explained as variations in a single, overarching component of intelligence known as g, he says. And researchers have recently shown that IQ scores are correlated with the amount of gray matter in certain brain regions, a finding that suggests that g is more than just a statistical construct.

"It suggests that g isn't just some artifact of the cognitive tests that we administer, but it actually exists in the brain," says Plomin.

However, Dennis Garlick, PhD, a psychologist at the University of Sydney, cautions that even the well-validated discovery of a gene that influences intelligence may not be as exciting as it initially sounds.

"Finding the specific genes for intelligence is merely confirming what we already know existed," says Garlick. "It is still a long road from identifying the genes responsible for intelligence to actually understanding what they do, and hence understanding how intelligence is inherited."

Plomin agrees that understanding how genes for intelligence work--not simply knowing that they exist--is critical. In one project, he and his collaborators are trying to find an animal model of g that could be used to study how genes influence intelligence. So far, they have tested 500 genetically diverse mice on a variety of cognitive tasks and found evidence suggesting that, just as a large portion of the variation among humans can be explained by differences in g, much of the variation among mice can be explained by a "mouse g."

"If we find a gene that's associated with g in humans, we want to then find out if that gene is associated with some cognitive process, or with g, in mice," says Plomin. "The name of the game is functional genomics--understanding how genes work."

But some researchers, such as University of Alberta mouse researcher Douglas Wahlsten, PhD, doubt whether mouse and human intelligence are really comparable.

"I certainly would not use the term intelligence to describe what we are measuring with our mazes," says Wahlsten. "The relation between mouse genes that alter learning and possible genes that alter human IQ remains to be explored."