Luca might be a movie about sea monsters, but where the sound of Pixar’s films is concerned, it’s the closest thing to one set in the real world. True, teenage Luca lives underwater with his fish-finned family, but when he steps out of the water and into an Italian fishing village, he becomes a human boy in the very recognizable 1960s, a time period fixed by the pop music that is frequently blaring from tiny portable radios.

Where an American coming-of-age movie set at the time would be scored with the rebellious tumult of early rock ’n’ roll, Luca’s soundtrack leans on the sounds of artists like Gianni Morandi and Rita Pavone, whose brassy anarchy has a flavor all its own. We talked to director and co-writer Enrico Casarosa, who based the story on his own childhood memories, about picking the songs and breaking Pixar’s unwritten rule against needle-drops.