Organizationa Behaviour

Given that a substantial amount of intellectual ability is

inherited, it might surprise you to learn that intelligence test

scores are rising. In fact, scores have risen so dramatically

that today’s great-grandparents seem mentally deficient by

comparison. First, let’s review the evidence for rising test

scores. Then we’ll review explanations for the results.

On an IQ scale where 100 is the average, scores have

been rising about 3 points per decade, meaning if your

grandparent scored 100, the average score for your

generation would be around 115. That’s a pretty big

difference—about a standard deviation, meaning someone

from your grandparent’s generation whose score was at the

84th percentile would be only average (50th percentile) by

today’s norms.

James Flynn is a New Zealand researcher credited

with first documenting the rising scores. He reported the

results in 1984, when he found that almost everyone who

took a well-validated IQ test in the 1970s did better than

those who took one in the 1940s. The results appear to

hold up across cultures. Test scores are rising not only in

the United States but in most other countries in which the

effect has been tested, too.

What explains the Flynn effect? Researchers are not

entirely sure, but some of the explanations offered are these:

1. Education. Students today are better educated than

their ancestors, and education leads to higher test scores.

2. Smaller families. In 1900, the average couple had

four children; today the number is fewer than two. We

know firstborns tend to have higher IQs than other

children, probably because they receive more attention

than their later-born siblings.

3. Test-taking savvy. Today’s children have been tested

so often that they are test-savvy: they know how to take

tests and how to do well on them.

4. Genes. Although smart couples tend to have fewer,

not more, children (which might lead us to expect

intelligence in the population to drop over time),...