Bernadette: Well, if it makes you feel any better, I'm never speaking to Priya again.
Penny: No, don't do that. No reason to be mean to her.
Amy: This may be the alcohol talking, but I believe there is. Are you familiar with the recent study of Tanzanian chimpanzees by Nishida and Hosaka out of Kyoto University?
Penny: No, but I can name all the Kardashians.
Amy: Primates, such as ourselves, have a natural instinct to ostracize ill-mannered members of the troop. Bernadette's urge to shun, scowl or fling her waste at Priya is hard-wired into her DNA.
Bernadette: I don't have an urge to fling my waste.
Amy: Believe me, it's there, we all have it. Hit me with some more booze, and I'll show you.