Theodore: in-breeding may sometimes have a beneficial effect. Charles Darwin is an example, in fact; among others his family produced the Wedgwoods, the great composer Vaughan Williams, the Keyneses and a variety of other major contributors to British public life. They all tended to marry cousins too. On the other hand, they also suffered from depression much more often than others.

Jews are more ambitious than most other ethnicities. And they are also bookworms. Those two factors explain a lot. But why not take a more holistic approach? Intelligence is not measurable in Nobel prizes and so on. Wisdom is worth immensely more than cleverness.

“Humankind cannot bear very much reality.” More evidence for this was given by a survey of people’s assessment of the probability of various events taking place. It was found that “normal” people thought bad things less likely to happen and good things more likely to happen than is actually the case. Clinically depressed people got the likelihood right however. As one of the people conducting the survey put it: psychologically, sanity is being in a completely unjustified state of optimism.

However, the fact remains that intellectual output of the Jews is completely disproportionate to their relatively small numbers. Perhaps, it’s simply a culture of learning, or perhaps it’s genetics, or perhaps, as I suspect, it’s a combination of many factors; but regardless it’s interesting and worth investigating (and understanding).

Now, if intelligence isn’t entirely innate, then what about religiousness?

There is a great deal of conflicting evidence about intellect and genes or environment, as well as intellect and achievement.

there are studies that show firstborns are the most intelligent of the children, and that self discipline by the age of 5 correlates better with achievement as an adult better than IQ.

For a community to maintain its gene pool as regards intelligence doesn’t require conscious eugenics; a possible reason why Jews do so well is that the Jewish communities in Europe were overwhelmingly literate and that scholars, such as rabbis, were not celibate unlike among their neighbouring Christians. It was considered a good match for a girl to marry a rabbi; Catholic intellectual life was almost entirely conducted among celibate priests and monastics, so they did not pass whatever genes they had down to the next generation. Even in the Protestant world, where priests married, a marriage to a priest wasn’t seen as advantageous. Generally speaking, Jews in Europe were literate (and despite their persecution, had higher standards of living than others in the parts of Europe where they lived).

As for that table, obviously poorer countries with poorer education systems score lower. It just goes to show that IQ doesn’t measure innate, i.e. genetic, intelligence.

Jewish people maybe more academically inclined because of a long-standing cultural tradition of valuing scholarship, rather than because they are genetically more gifted with “intelligence”.

And Muslims should know this from their own history, how well the Islamic nation excelled in the sciences at a time when there was such a high value for scholarship within the Islamic world.