All this discussion about encoding information has finally dredged up a memory of an anecdote about Alekhine, a world champion chess player after WW1. He used to give exhibitions in which he’d play simultaneous games against 12 players blindfold! He’d sit with his back to the audience, blindfolded and the players called out their moves to him. I think the record since is close to 70 but Alekhine was usually playing drunk which the others didn’t - I consider that cheating.
Anyway, he was asked how he remembered all those game and he explained that he imagined a tall chest of drawers and each time a move was called out, the sound of the player’s voice opened the right drawer.
I think of that as an “associate array” from software. Kind of an indexed list but not necessarily in order.