A meme is “an idea, behavior, or style that spreads from person to person within a culture.” A meme acts as a unit for carrying cultural ideas, symbols, or practices that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena. Supporters of the concept regard memes as cultural analogues to genes in that they self-replicate, mutate, and respond to selective pressures.
It was coined by the British evolutionary biologist Richard Dawkins in The Selfish Gene as a concept for discussion of evolutionary principles in explaining the spread of ideas and cultural phenomena. Examples of memes given in the book included melodies, catch-phrases, fashion, and the technology of building arches.
Dawkins used the term to refer to any cultural entity that an observer might consider a replicator. He hypothesized that one could view many cultural entities as replicators, and pointed to melodies, fashions and learned skills as examples. Memes generally replicate through exposure to humans, who have evolved as efficient copiers of information and behaviour.
Dawkins defined the meme as a unit of cultural transmission, or a unit of imitation and replication, but later definitions would vary.
Memes, analogously to genes, vary in their aptitude to replicate; successful memes remain and spread, whereas unfit ones stall and are forgotten. Thus “better” memes are selected.
Memes first need retention. The longer a meme stays in its hosts, the higher its chances of propagation are. When a host uses a meme, the meme’s life is extended. The reuse of the neural space hosting a certain meme’s copy to host different memes is the greatest threat to that meme’s copy.
A meme which increases the longevity of its hosts will generally survive longer. On the contrary, a meme which shortens the longevity of its hosts will tend to disappear faster. However, as hosts are mortal, retention is not sufficient to perpetuate a meme in the long term; memes also need transmission.
Life-forms can transmit information both vertically, from parent to child, via replication of genes, and horizontally through viruses and other means. Malcolm Gladwell wrote, “A meme is an idea that behaves like a virus–that moves through a population, taking hold in each person it infects.” Memes can replicate vertically or horizontally within a single biological generation. They may also lie dormant for long periods of time.