INTELLIGENCEstood at over thirty countries. Rather than our brains having undergone
some kind of collective upgrade, however, Flynn thinks the explanation
lies in the rise of science education and technology.
If you look closely at the intelligence-test subscales, our collective
improvement hasn’t been uniform. On general knowledge, maths and
vocabulary we’ve barely budged, whereas our skill at typical questions
about similarity (such as “in what ways are dogs and rabbits alike?”) have
rocketed. This fits Flynn’s explanation, because he says that a youth of
today would be taught that dogs and rabbits are both mammals (the
kind of answer that a typical intelligence-test would be after), whereas
the youth of yesteryear would be taught to focus on what things are for,
in this case that a dog is for hunting rabbits. We’ve also shown signifi-
cant average improvement on Raven’s Progressive Matrices and other
abstract tests. Again, Flynn says that this probably reflects the ubiquity
of visual and abstract stimulation in the modern world, in the form of
video games and TVs.
After years of IQ increases, a surprising study published in 2008
suggested that a recent change of direction might have occurred,
with average intelligence-test performance beginning to decline.
Thomas Teasdale at the University of Copenhagen and David Owen of
the City University of New York took advantage of the Danish tradi-
tion of testing the intelligence of all eighteen-year-old men prior to
conscription into military service. Consistent with the Flynn effect,
the 25,000 young men assessed for military service in Denmark in
1999 performed significantly better, by about two IQ points, than the
33,000 tested in 1988. However, the 23,000 men tested in 2003–2004
performed significantly worse than the 1998 group, at a level almost
equivalent to the 1988 group. A similar observation has been made
among Norwegian conscripts.
What could be causing this reversal in braininess? Teasdale and Owen
ruled out diet change as the cause – after all, there had been no shift in
average height, which you’d expect if diet had altered. They also rejected
the suggestion that the decline could be due to malingering, since test
performance was actually higher among men with a more negative
attitude to the military. Instead, the researchers surmised that there has
been some kind of reduced emphasis on abstract reasoning and problem-
solving in the Danish educational system, or a decreased emphasis on
speed. Whatever the cause, Teasdale and Owen predicted that this new
trend could meet with the emerging Flynn effect in Third World coun-
tries, thus leading to a levelling of IQ scores around the world.