Lisa's Brain: Poor predictable Bart; always takes Rock.
Bart's Brain: Good ol' Rock, nothing beats that!
Why is the game "Rock-paper-scissors" known in the UK as "Paper-scissors-stone"? Is there anyone who is paid or gets a scholarship to figure that out? I want that gig.
No matter the nomenclature, it was invented in Japan in the 19th century; what makes it interesting is that it one can be 'good' at it. It's very hard for humans to act in a truly random fashion. Different people have different 'strategies' and if you know what the other person is likely to 'throw', it's possible to regularly beat them. (see Bart v. Lisa).
A great RPS moment was from "Pete & Pete". The kids are terrorized by a bully named "Papercut", who forces them all to play RPS. He always throws (what else?) paper, but the kids are too scared of him to throw anything but rock. Little Pete defies him by throwing scissors, enraging Papercut, who demands a rematch. With the help of his friends, Little Pete comes up with the breakthrough strategy of throwing "Meteor" and "Volcano", and ends Papercut's reign of terror. I think they still teach that one at West Point.
Check out Poor Predictable Rock for more on how the flaw in Bart's logic pervades a lot of pop-culture 'worlds'.