Google yeilds nothing with my hook baited with the thread title, but I do recall it being in Disney style. A baby has a caveman in his head, then when he’s older has the caveman and a puritanical scold both in his head, driving him like a car. Later he meets a girl, and she has a 50’s bobbysoxer and a prim spinster driving her.
Anyone else remember this rare foray (June Foray?) by Walt into Freudian theory?
Besides his examination of Freudian fixation on the buttocks: every single one of his other cartoons.
I believe the cartoon you’re thinking of is the 1943 Walt Disney anti-Nazi short Reason and Emotion. Later, Disney recycled the non-propaganda portion of the short for a Ludwig Von Drake episode of the “Wonderful World of Disney” about psychology which is where most people saw it.