The web adress:
http://www.amsci.org/amsci/articles/97articles/Neisser.html
points to an article that briefly discusses several possible
explanations for the Flynn effect.
Rising Scores on Intelligence Tests
Ulric Neisser
American Scientist
September-October 1997
Abstract
All over the world, average scores on intelligence tests have been
rising for the better part of a century--essentially ever since such
tests were invented. For example, average scores on standard
broad-spectrum IQ tests are going up by about three points-relative to
a mean of 100--every 10 years, and the increases are even higher on
specialized measures of abstract-reasoning ability. The cause of these
enormous gains remains unknown. No one knows if they reflect genuine
increases in intelligence or just a gradual spread of some specialized
knack for taking tests. Greater sophistication about tests surely
plays some role in the rise, and other possible contributing factors
include better nutrition, more schooling, altered child-rearing
practices and the technology-driven changes of culture itself. Neisser
explores these factors, and concludes that our highly visual
environment may play a fundamental role in the increases in IQ scores.
Here are two semi-provocative excerpts:
These gains are far too rapid to result from genetic changes. There
evidently are substantial environmental influences on g, even if we do
not clearly understand them at the present time. Moreover, the sheer
size of the gains undermines the very concept of general
intelligence.
...
As Flynn puts it, the data imply that dozens of nations should now be
in the midst of a cultural renaissance too great to be
overlooked. Because that does not seem to be happening, Flynn
concludes that the tests do not measure intelligence but only a minor
sort of abstract problem-solving ability with little practical
significance.
...
Author Neisser suggests the following (partial) explanation for the
Flynn effect: "exposure to complex visual media has produced genuine
increases in a significant form of intelligence."
Begin Neisser excerpt:
Perhaps the most striking 20th-century change in the human
intellectual environment has come from the increase in exposure to
many types of visual media. From pictures on the wall to movies to
television to video games to computers, each successive generation has
been exposed to far richer optical displays than the one
before. People once regarded pictures as museum pieces or as
occasional decorations for the homes of the rich; now they are
everywhere, and everybody takes their own photographs. Schoolchildren
of all ages devote far more time to visual projects today than they
did a generation ago. (They devote correspondingly less time to the
old three Rs of reading, writing and arithmetic, with the predictable
consequence that skills in those domains have diminished.)
Beyond merely looking at pictures, we analyze them. Picture puzzles,
mazes, exploded views and complex montages appear everywhere--on
cereal boxes, on McDonalds wrappers, in the instructions for
assembling toys and in books intended to help children pass the
time. Even the answer sheets for standardized tests--often on pages
separate from the questions--assume that the test-takers can locate
the right places to record their responses. And static displays such
as pictures and diagrams are only the beginning. We have had movies
since the 1920s, television since the 1950s and video games since the
1970s. Patricia Greenfield of the University of California at Los
Angeles argues that children exposed to these media develop specific
skills of visual analysis, skills in which they routinely excel their
elders. The assumption that children can program a VCR more
effectively than their parents has become a cliche of American
society, one that recognizes an important generational shift.
End of Neisser excerpt
Gregory Sullivan http://www.cs.jhu.edu/~sullivan