Penny: You know, I’ve done this before. In kindergarten, I was supposed to marry Jason Sorensen at recess, but by the time my class got out there, he was already engaged to Chelsea Himmelfarb. So what did I do? Hung upside down from the monkey bars, let all the boys see my underpants.

Amy: You can’t blame yourself. When your prefrontal cortex fails to make you happy, promiscuity rewards you with the needed flood of dopamine. We neurobiologists refer to this as the skank reflex.