I would guess because its a cheap (in terms of time) way to search for really bright people. Obviously not the only way, and not fool-proof, but if you find som

I would guess because its a cheap (in terms of time) way to search for really bright people. Obviously not the only way, and not fool-proof, but if you find someone who loves math and science enough to devote ~10 years of their life to it, chances are they're pretty sharp - at least in certain ways. I wouldn't say their patterns and algos "need" that level of research. But what a hedge fund doesn't have is a lot of time to waste interviewing junior programmers/undergrads hoping to find nuggets of wheat in the chaff.