Excellent post!

Males in the lucky guesser group chose the performance-inhibiting drug significantly more than those in the control group

I managed to guess this; my parents got it wrong. I thought that the control group would feel good about being right, and want it to occur more, whereas the unconfident group would feel (nihilistic? apathetic?), and so take the easy high of the drugs.

I confess I thought that the performance inhibiting drugs were euphoric; I couldn't imagine why anyone would take inhibiting drugs without some beneficial side effects. If this was wrong, I was effectively answering a different credit, so can’t really take credit for my guess.