Well, it's also the way the kids are raised from young that can have an effect on IQ, regardless of race, religion, ethnicity. In many Jewish homes, in Asian homes, in Russian and Soviet era homes, (it's also true in other homes, of course, but these stand out because among these groups, most seem to do it), the stereotype, true or not, is that children are encouraged from a young age to ask questions, to think for themselves, to work hard at academics, to appreciate the arts - music, art, theatre, to appreciate food and culture, fine dining. A standard is set for excellence, achievement. Not many disappoint. Or at least, the bar is set higher.
And that's unrelated to native intelligence?
Jews appreciate fine dining? You've got to be kidding me. We are the people of corned beef and falafel.