A meme (pronounced... rhyming with "cream") is a postulated unit of cultural ideas, symbols or practices, which can be transmitted from one mind to another through writing, speech, gestures, rituals or other imitable phenomena. (The etymology of the term relates to the Greek word μιμητισμός ([mɪmetɪsmos]) for "something imitated".) Supporters of the concept regard memes as cultural analogues to genes, in that they self-replicate and respond to selective pressures.
The British scientist Richard Dawkins coined (or adapted) the word "meme" in The Selfish Gene (1976) 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, beliefs (notably religious beliefs), clothing fashion, and the technology of building arches.
Meme-theorists contend that memes evolve by natural selection (in a manner analogous to that of biological evolution) through the processes of variation, mutation, competition, and inheritance influencing an individual meme's reproductive success. Memes spread through the behaviors that they generate in their hosts. Memes that propagate less prolifically may become extinct, while others may survive, spread, and (for better or for worse) mutate. Theorists point out that memes which replicate the most effectively spread best, and some memes may replicate effectively even when they prove detrimental to the welfare of their hosts.
A field of study called memetics arose in the 1990s to explore the concepts and transmission of memes in terms of an evolutionary model. Criticism from a variety of fronts has challenged the notion that scholarship can examine memes empirically. Some commentators question the idea that one can meaningfully categorize culture in terms of discrete units."
Information source: Wikipedia
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"The word meme originated with Dawkins' 1976 book The Selfish Gene. To emphasize commonality with genes, Dawkins coined the term "meme" by shortening "mimeme", which derives from the Greek word mimema ("something imitated")