8:52 PM 3/15/1998

Experts at loss to explain large jump in average IQ

Older generation likely smarting over data

Copyright 1998 Houston Chronicle Science Writer

In modern memory, the younger generation rarely has had any doubt it is smarter than the older generation. Now, there may be data to suggest it's right.

IQ scores are rising so dramatically, say researchers who study intelligence, that a high proportion of people considered average at the turn of the 20th century would be regarded as significantly below average by today's tests.

"People are smarter now, they know more," says Cecil Reynolds, a Texas A&M University professor of neuroscience and educational psychology. "Children are stimulated at an early age by a more complicated world, fostering neurological development."

More specifically, psychologists cite as likely explanations better education, improved socioeconomic status, healthier nutrition, smaller families, urbanization, even television and video games making minds more agile.

But critics, most of them opponents of IQ testing itself, argue the rise is not so much proof of greater intelligence as it is of greater sophistication about test taking. Moreover, they argue that the increase is evidence of what's wrong with IQ testing.

One explanation for the increase is not possible: heredity. Because the rise has taken place in such a short time -- three IQ points per decade in the United States -- it cannot be because of genetic factors.

Yet no one is positive what truly is the cause, and uncertainty about that -- and what it means -- is only exacerbated by the absence of a simultaneous rise in scores on achievement tests like the SAT.

"It's a genuine mystery," said John Loehlin, a University of Texas-Austin professor of psychology. "All of the explanations given are probably true, but it's still hard to see how they would account for such a large jump."

In their most primitive form, IQ tests date to the 19th century but they became widely used only in the early 20th century and considered reliable in the 1930s. More popular now than ever despite controversy over how well they take into account differences in race and class, they are given in schools to students suspected of a learning disability or applying for "gifted" programs as well as in clincal practice and in many employment settings, like the military or law enforcement.

The steady rise in their scores was not apparent before because the tests are regularly adjusted, or renormed, so half the takers score below 100 and half above, regardless of how many questions are answered correctly.

The worldwide pattern of rising IQ scores was discovered by studying results of those tests that have not been revised over decades, such as those used by the military; and by studying scores of people who took both versions of a given IQ test -- the current one and the forthcoming replacement. Nearly always, people scored higher on the old test.

The largest gains were found on Raven's Progressive Matrices, which measure abstract reasoning ability by relying on shapes rather than words. Its scores have grown an average of six points per decade, meaning that people who scored in the top 10 percent in the late 19th century would score in the bottom 5 percent today.

On two more commonly used tests -- the Stanford-Binet and the Wechsler Scales -- the increases were only about 3 points per decade. But if their sections reflecting knowledge acquired over time were eliminated to consider only those sections measuring abstract reasoning skills, the increases would jump to six points.

"But the question is, what do you mean by intelligence?" asks Dov Liberman, a University of Houston professor of educational psychology and ardent opponent of the most common IQ tests. "Intelligence is a multi-faceted thing, incapable of being summed up by one number, and all a consistent rise in IQ test scores tells you is that people have learned better how to take them."

Liberman points to the growing industry of "test-preparation" companies and argues it is no coincidence that scores go up on IQ tests that haven't been revised, then go down when new versions are used.

Indeed, points out Rice psychology professor Mickey Quinones, the increase in scores is proof of how much IQ tests are susceptible to the environment -- educational background, emotional state -- instead of just measuring the immutable, inheritable thing psychologists have long assumed intelligence to be. The biggest IQ gains, for instance, have come among those at the bottom end, at a time the government invested more in equalizing education for minority children.

But does that mean people are smarter today? One expert argues that the reason IQ scores are increasing but achievement tests aren't is that fluid intelligence, the ability to learn how to do something, is growing while crystallized intelligence, the possession of information, is decreasing. That's why children from the 1930s who would do badly on Raven's would likely outperform today's kids on questions about literature or history.

Fluid intelligence -- UT psychology professor Joe Horn describes it as a greater societal stress on cleverness -- is nurtured everywhere. For instance, kids now encounter mazes and puzzles, all appearing in formats similar to those used on IQ tests, everywhere from software to cereal boxes. A maze used on a place mat at the International House of Pancakes is identical to one used on a Wechsler test.

And several studies have shown that playing video games actually improves children's performance on IQ-type tests. One found that after playing a video game that required them to manipulate an object as if it were moving through 3-dimensional space, children performed better on a mental paper-folding task similar to ones found on the Wechsler and Stanford-Binet tests

Nevertheless, skeptics wonder if we are really so much smarter now, where are today's Michaelangelos or Shakespeares? People like A&M's Reynolds respond that the new skills are instead manifested in this era's achievements in science and technology -- DNA, for instance, or computers. They also say increased intelligence shouldn't unsettle people.

"I don't mean to sound Darwinian, but our very chances of survival depend on becoming smarter," says Reynolds. "If intelligence doesn't increase while the world's complexity does, we're doomed."