Comment by nartho

Maybe, but let say you're right. I still don't understand your suggestion of doing an IQ test before you decide to study math. If you can't go further than a masters, like you said there are still a lot of industries you can go too and have an interesting, lucrative job. And if you do succeed to finish your PhD then that's great news. There are no benefits that I can see in doing an IQ test like you suggested before you make your decision. If you love math and are good at it, chances are you're moderately smart at least. Might as well go as far as you can if that's what you want.