Not wanting to add to the title, but if HN had a subtitle, this would be it: "The effect is only present in courses with significant teacher–student interactio

Not wanting to add to the title, but if HN had a subtitle, this would be it: "The effect is only present in courses with significant teacher–student interaction." I mention this because I initially wondered if looks drove general confidence, and that somehow made them better students. But the subtitle implies that instructors have a bias in favor of looks. That said, now I wonder how the gender and/or gender-preference of the teacher influences the bias.