In the past few decades that The Simpsons has dominated television, you may have found yourself asking a very logical question: why do virtually all of the adult-oriented sitcom’s characters have yellow skin? While there are a wealth of weird theories floating around the internet, the answer may be a lot simpler than you expect.

Series creator Matt Groening has revealed that the reason for his characters’ unusual skin color was – first and foremost – economical. In a 2000 documentary dissecting his career, the animator recalled when, how and why the decision was made.

“If you’re flicking around with your channel changer very fast,” he said, “and you zoom by The Simpsons and there’s nothing else that looks like them on TV, they stand out.”

Standing out was important, not because there were a lot of adult-oriented cartoons, but because there weren’t any at all. Around the time...