In the summer of 2000 scientists celebrated the near complete mapping of the human genome . This sequencing was a huge milestone because genes determine our bodies' structure and function. It is the slight changes in genes, called mutations , that create variations and make possible the dramatic changes of evolution.
But more than genes change. Our ideas, catch phrases, beliefs, games, and creations also evolve. Think of the differences between Ice Age cave art and modern painting, the chants and songs of centuries-ago people and the crooning of Britney Spears, the stone axe and the atomic bomb. Is there something gene-like that carries culture?
One provocative theory holds that culture is carried forward by memes, units of ideas, habits, skills, stories, customs, and beliefs that are passed from one person to another by imitation or teaching. Memes are, in effect, units of information that are self-replicating and changeable, just as genes are. It has been said that a chicken is just the egg's way of making another egg. In that same way, one might argue that people are simply memes' way of making more memes.
As with genetic traits, competition among memes through natural selection yields winners and losers.
Memes can be transmitted through teaching or imitation. For example, jump-rope rhymes or the spread spread of the periodic table among people through practiced repetition.
Culture is "a mass of memes," says theorist Susan Blackmore. She points to myths, inventions, language, and political systems as structures made of memes. Not everything is a meme. Skiing may be a meme, but the personal skills and experience of skiing are not.
What good are memes? To some social scientists, they give new insights into how culture is maintained and transmitted among people and over generations. For most of human history, memes and genes evolved in lockstep, biology and culture proceeding hand in hand. Now, however, memes have raced far ahead of biological change. What better example is there of this phenomenon than the Internet, a meme itself and a lightning-fast transmitter of memes.
Some critics, though, have yet to be persuaded. They contend that memes have not been defined satisfactorily. No one has isolated a meme the way scientists have isolated single genes; nor has meme theory been studied and used to make predictions, as genetic theory has.
Nevertheless, the theory of memes, though flawed, remains one of the leading ways of thinking about cultural evolution. And, of course, the theory is a meme itself.