Are people smarter in Japan?

Japan's dazzling commercial success may be due partly to the fact that, in some sense, the Japanese have been getting smarter.

British psychologist Richard Lynn says this is implied by his study of Japanese IQs. The average IQ for Japan's younger generation is about 111. That's the highest in the world, and some 11 points above the statistics for Western Europe and the United States.

Presenting his findings in the science journal, Nature, Mr. Lynn, of the New University of Ulster at Londonderry, notes that Japanese average IQs have been rising during this century. The gap between the US and Japanese IQ levels has widened throughout that period.

What is more, Mr. Lynn points out, about 10 percent of Japan's population has an IQ level above 130, compared to about 2 percent for the populations of Western Europe and the US. That's the general level of professional groups such as engineers or lawyers. Also, some 77 percent of the Japanese have IQs above the European and US averages.

One should note at this point that there is no agreement among psychologists as to what IQ tests measure. Commenting on the Lynn paper, the journal Nature itself observes: ''Whether the difference in IQ represents a real difference in 'intelligence' or simply implies that the Japanese are better at IQ tests, remains open to question.''

Nonetheless, to whatever extent such tests are related to intellectual abilities, the Lynn findings are intriguing. To begin with, there is no easy explanation for them.

The rise in average IQ - about 7 points in the course of a generation - has been too rapid to be explained by evolutionists as representing change in the genetic makeup of the Japanese population, Mr. Lynn says. Nature, in its comment , does note that wholesale migration from isolated villages to industrial centers in recent decades has greatly reduced inbreeding. However, Mr. Lynn says he thinks environmental factors, especially improved nutrition, are more likely to be important.

The role of education is unclear. Mr. Lynn notes that the rise in IQ was detected even among six-year-old children. ''This,'' he says, ''indicates that it cannot be explained in terms of improvements in education and must be attributed to effects taking place before the age of six.'' Nevertheless, the move from village to city has put many intellectually talented Japanese into a far more stimulating environment than they would have enjoyed a few decades ago - an environment where talent can be recognized, encouraged, and tested.

It is impossible to judge whether the IQ gap means the Japanese are fundamentally more intelligent than Western populations. But the challenge to the US, in particular, is clear. The Japanese have a rich supply of human talent which that nation's educational system nurtures and encourages. The US likewise is richly endowed. But with educational cutbacks at local and federal levels, its intellectual talents are undernourished. This is especially true of precollege science and mathematics teaching. If the US is to meet Japanese competition, it cannot afford shoddy education.