Before it was a cat photo with a funny caption, the word “meme” had a much broader meaning. It describes any idea, behavior, or style that spreads from person to person within a culture. Think of fashion trends, catchy song melodies, or popular sayings. These are all memes in the original sense of the word.

The term was coined in 1976 by evolutionary biologist Richard Dawkins. He wanted a word to describe how cultural information spreads, similar to how genes spread biological information. A meme is essentially a unit of culture.

Just like genes, memes compete for survival. They replicate when people imitate them, they can mutate as people change them slightly, and they evolve as certain versions become more popular and spread more widely than others. The most successful memes are the ones that are easily remembered, repeated, and passed on.

This process of cultural transmission is as old as humanity itself. Long before we had screens, ideas traveled by word of mouth, through art, and by simple repetition. One of the most famous early examples is a piece of graffiti that followed soldiers around the world.

During World War II, American GIs started scribbling this phrase and a simple doodle wherever they went. The drawing showed a little man with a long nose peeking over a wall. It appeared on ships, in barracks, and on captured enemy forts. No one is entirely sure how it started, but it spread like wildfire. It was a shared joke, a sign of American presence, and a way for soldiers to leave their mark.

Kilroy is a perfect example of a pre-internet meme. It had a simple, replicable format. It carried a shared meaning for a specific group. And it spread far and wide through simple human imitation.

This concept of a meme as a cultural building block is the foundation for understanding how ideas, both simple and complex, take hold and shape our world.