This explanation rings very true in the lives of the post-college people I know. Indeed I think this is the strongest effect in the system: the spreads between

This explanation rings very true in the lives of the post-college people I know. Indeed I think this is the strongest effect in the system: the spreads between the two financial groups are about 10-20% at all points EXCEPT FOR the spread for males in the 20-30 age group where the spread looks more like 50%. It doesn't surprise me that females aged 20-30 don't show this spread. I'd expect to see a similar dynamic in sex versus grades for college age males. It's the stereotypical example of partying versus studying on a Thursday or Friday night, with $$$ substituted for grades!