Good-looking people do better in exams than ugly ones. That's the message of this paper (pdf):
We examine the effects of students' physical appearance upon examination results. We fund evidence that beauty has a significant impact on academic performance, a result which is consistent with and comparable to the impact found in labour market literature.
The effect is big. Students with looks that are one standard deviation above average perform 38% better than those with looks one standard deviation below average.
The effect differs between men and women. Among men, the beauty premium exists because ugly men do really badly. Among women, there's no penalty for munters, but a small premium for lookers, which suggests Carol's an outlier.
Fascinatingly, the beauty premium is greater in written exams than oral ones. This suggests the pay-off to good looks (or a lack of ugliness) comes from higher ability rather than discrimination.
This might be because of the Kathy syndrome: beauty and intelligence are correlated (pdf). Or it might be that beauty leads to greater self-confidence, which encourages people to study more in the belief that hard work will pay. Or it might be that mingers are more likely to be bullied at school, which retards their intellectual development.
There is a puzzle here. Because the study is confined to economics students, it suggests that being an ugly man is a drawback to becoming a good economist. But there is abundant evidence to the contrary.