SCIENCE OBSERVER
Smart as We Can Get?
David Schneider
Psychometricians have long been aware of a phenomenon called the
Flynn effect—a widespread and long-standing tendency for
scores on certain tests of intelligence to rise over time. The
effect is most pronounced in tests of so-called fluid intelligence,
such as those that require the subject to identify the missing
element in an array of figures. In the early 1980s, James R. Flynn,
now an emeritus professor at the University of Otago in Dunedin, New
Zealand, found strong evidence for this trend when he compared some
newly introduced IQ tests with the older versions they replaced:
When the same people took both tests, they appeared smarter when
scored on the older exams compared with the new. If results were not
continually normalized so that the mean score was 100, the IQ of
test-takers would rise over time—and by a large amount: about
3 points or more per decade.
Ever since Flynn published his startling results, psychologists and
educators have struggled to figure out whether people really are
getting smarter and, if so, why. No clear answer has emerged. And
now they have another curiosity to ponder: The tendency for
intelligence scores to rise appears to have ended in some places.
Indeed, it seems that some countries are experiencing a Flynn effect
with a reversed sign.
The strongest indications have come from Scandinavia. In 2004, Jon
Martin Sundet of the University of Oslo along with two colleagues
from the Psychological Services branch of the Norwegian Armed Forces
published a article in the journal Intelligence documenting
the evolution of scores on intelligence tests given to Norwegian
conscripts between the 1950s and 2002. Although the first two
decades of testing produced ever-better results, consistent with the
ubiquitous Flynn effect, gains began to slow in the 1970s and '80s,
and the increase in scores of general intelligence stopped after the
mid-1990s. Scores on tests of arithmetic skills in particular began
to slide distinctly backward after that time.
Last year, Thomas W. Teasdale of the University of Copenhagen and
David R. Owen of Brooklyn College, City University of New York,
discovered similar goings-on in nearby Denmark. They, too, looked at
tests of intelligence given to military recruits (which for Denmark
means just about all 18-year-old men). And they also found that
overall scores, which had been rising for decades, reached a
plateau. "Across the ‘90s, all of the tests
stagnated," says Teasdale, referring to the four separate tests
given to these men: one involving logical reasoning, another using
verbal analogies, a third on completing number series and a fourth
test of spatial ability that used geometric figures.
Further indications that scores on intelligence tests are not
universally climbing have come from the United Kingdom. In an
article soon to be published in the British Journal of
Educational Psychology, Michael Shayer, a psychologist at
King's College, University of London, and two colleagues report that
performance on tests of physical reasoning given to children
entering British secondary schools declined markedly between 1976
and 2003.
The test at issue here, based on a methodology pioneered by the
Swiss developmental psychologist Jean Piaget, involved asking
students to reason about the conservation of liquid and solid
materials, the conservation of internal volume and volume
displacements—a battery known as the Piagetian
volume-and-heaviness tests. Shayer and his colleagues found a rather
astounding, 25-percentile-point decline in the last quarter-century.
"The kids now at 11 years and 10 months are doing as well as
the eight- to nine-year-olds in 1976," Shayer explains. Shayer
posits that a distinct shift in the environment is at work—in
particular, diminishing amounts of experiential play. "They're
glued to bloody computer games," he laments, adding that
"the food computers offer children is thin gruel indeed."
Flynn himself is much less gloomy about what appears to be
happening. For one, he points out that the situation varies quite a
bit from country to country. "All the evidence is that the IQ
gains in America are still robust, " he says. And he notes that
at the very time that scores were declining in the UK on the
Piagetian tests that Shayer examined, British kids were making gains
on a test called the Wechsler Intelligence Scale for Children or
WISC. Flynn points out that results gathered with two versions of
this test (WISC-III, introduced in 1991, and WISC-IV, in 2003) show
the usual effect, a rise in raw scores over time. But he also notes
that one subtest—on arithmetic reasoning—did show a decline.
Although Flynn cautions against generalizing the recent Danish and
Norwegian experiences, he anticipates similar results will crop up
elsewhere in the world. But he's not glum about it. Flynn is
convinced that the cause of his eponymous effect has to do with
changes in the environment that allow children more opportunity to
exercise the kinds of skills probed in today's intelligence
tests—changes like a shift to smaller family sizes, which
allow parents more time to interact with each child, for example, or
devotion of an ever-greater portion of kids' leisure time to
abstract, mentally demanding games. He points out that in
industrialized, middle-class countries (like those of Scandinavia),
such influences must be reaching a point of saturation: "You
can't really get the family much smaller than one or two kids."
And the current craze for Sudoku puzzles not withstanding, as Flynn
says, "eventually, people do want to relax."
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