"Bar Psychology" joke

A very shy guy goes into a bar and sees a beautiful woman sitting at
the bar. After an hour of gathering up his courage he finally goes
over to her and asks, tentatively, "Um, would you mind if I chatted
with you for a while?"
She responds by yelling, at the top of her lungs, "No, I won't sleep
with you tonight!" Everyone in the bar is now staring at them.
Naturally, the guy is hopelessly and completely embarrassed and
he slinks back to his table.
After a few minutes, the woman walks over to him and apologizes. She
smiles at him and says, "I'm sorry if I embarrassed you. You see, I'm
a graduate student in psychology and I'm studying how people respond
to embarrassing situations."
To which he responds, at the top of his lungs, "What do you mean
$200?"