A Yiddishe Kop, or, How Come Jews Are So Smart

I recently read an interesting article in the Jewish Magazine, whose author, Arthur Rosen, expresses his personal opinion that the reason Jews are so smart is that they have been going yeshivas for centuries.  He even tells a couple of anecdotes to back up this opinion.  I have for a long time considered myself too old to read people's personal opinions (as opposed to science-backed theories and hypotheses), unless they are wrapped in beautiful poetic language.  However, I was interested in the topic, so I made an exception in this case.  As I read the article, I remembered that about a year ago I read a paper on this subject, so I looked it up.  This article is actually a scientific study and not just someone's personal opinion.  In fact, a cursory Google search can find a dozen similar sources that basically explain that (1) it's not all Jews, but specifically the Ashkenazi Jews that have IQ above average and (2) that it is most likely due to 500 years of discrimination, which restricted them from engaging in manual labor.  The Sephardim were not so restricted, and therefore did not develop the IQ of 105-117 on the average (nor did they develop the many genetic diseases that seem to go hand-in-hand with higher intelligence).