Memetics from Principia Cybernetica

Meme: an information pattern, held in an individual's memory, which is capable of being copied to another individual's memory.
Memetics: the theoretical and empirical science that studies the replication, spread and evolution of memes

Via  Principia Cybernetica

Cultural evolution, including the evolution of knowledge, can be modelled through the same basic principles of variation and selection that underly biological evolution. This implies a shift from genes as units of biological
information to a new type of units of cultural information: memes.

A meme is a cognitive or behavioral pattern that can be transmitted
from one individual to another one. Since the individual
who transmitted the meme will continue to carry it, the transmission can be
interpreted as a replication: a copy of the meme is made in the
memory of another individual, making him or her into a carrier
of the meme. This process of self-reproduction (the memetic life-cycle), leading to spreading over a
growing group of individuals, defines the meme as a replicator, similar in that
respect to the gene (Dawkins, 1976; Moritz, 1991).

Dawkins listed the following three characteristics for any successful replicator:

copying-fidelity:

the more faithful the copy, the more will remain of the initial pattern
after several rounds of copying. If a painting is reproduced by making
photocopies from photocopies, the underlying pattern will quickly
become unrecognizable.

fecundity:

the faster the rate of copying, the more the replicator will spread. An
industrial printing press can churn out many more copies of a text than
an office copying machine.

longevity:

the longer any instance of the replicating pattern survives, the more
copies can be made of it. A drawing made by etching lines in the sand
is likely to be erased before anybody could have photographed or
otherwise reproduced it.

Memes versus genes

In these
general characteristics, memes are similar to genes and to other
replicators, such as computer viruses or crystals. The genetic metaphor
for cultural transmission is limited, though. Genes can only be
transmitted from parent to child ("vertical transmission"). Memes can
be transmitted between any two individuals ("horizontal transmission"
or "multiple parenting"). In that sense they are more similar to
parasites or infections (cf. Cullen, 1998).

For genes to be transmitted, you need a generation. Memes only take
minutes to replicate, and thus have potentially much higher fecundity
(see Competition between Memes and Genes).
On the other hand, the copying-fidelity of memes is in general much
lower. If a story is spread by being told from person to person, the
final version will be very different from the original one. It is this
variability or fuzziness that perhaps distinguishes cultural patterns
most strikingly from DNA structures: every individual's version of an
idea or belief will be in some respect different from the others'. That
makes it difficult to analyse or delimit memes.
This does not imply that meme evolution cannot be accurately modeled,
though. After all, genetics was a well-established science long before
the precise DNA structure of genes was discovered.

Examples of
memes in the animal world are most bird songs, and certain techniques
for hunting or using tools that are passed from parents or the social
group to the youngsters (Bonner, 1980). In human society,
almost any cultural entity can be seen as a meme: religions, language,
fashions, songs, techniques, scientific theories and concepts,
conventions, traditions, etc. The defining characteristic of memes as
informational patterns, is that they can be replicated in unlimited
amounts by communication between individuals, independently of any
replication at the level of the genes.

Modelling memes

Memetics can be defined as an approach trying to model the evolution of
memes . Memes undergo processes of variation (mutation, recombination)
of their internal structure.
Different variants will compete for the limited memory space available
in different individuals. The most fit variants will win this
competition, and spread most extensively. This spreading can in
principle be modelled mathematically (see e.g. Boyd & Richerson,
1985; Cavalli-Sforza & Feldman, 1981; Lumsden & Wilson, 1981;
Csanyi, 1991; Lynch, 1998), although in practice it will be very
difficult to determine the exact values of the parameters of the model.
A more practical, qualitative approach is to formulate specific criteria for the fitness of a meme, relative to other memes, taking into account the subsequent stages of the memetic life-cycle.

As is the case with genes, it is not necessary to know the exact coding
or even
the exact size or boundaries of a meme in order to discuss its fitness,
and
thus to make predictions about its further spreading, survival or
extinction
within the population of competing memes. Such predictions can be
empirically tested. For example, a memetic hypothesis might state that
simpler memes will spread more quickly. This can be tested by observing
the spread (perhaps in a controlled environment) of two memes that are
similar in all respects, except that the one is simpler. Theories can
also be induced from empirical observation of meme behavior "in the
wild" (see e.g. Best, 1998). Given the differences in variation and
selection mechanisms, it is also possible to make predictions about the
competition between memes and genes.

Variation, replication and selection on the basis of meme fitness
determine a complex dynamics. This dynamics will be influenced by the
medium through which memes are communicated, and the copying-fidelity,
fecundity and longevity it allows. Perhaps the most powerful medium for
meme transmission is the computer network, and this implies some
specific characteristics for memes on the net.

References:

• Aunger R. (ed.) (2000): Darwinizing Culture: The Status of Memetics as a Science,
  Oxford University Press.
• Best, M., L., 1997; Models for Interacting Populations of Memes: Competition and Niche Behavior. Journal of Memetics - Evolutionary Models of Information Transmission, 1.
• Blackmore S. (2000): The Meme Machine, (Oxford Univ. Press).
• Bonner J.T. (1980): The Evolution of Culture in Animals, (Princeton University Press, Princeton).
• Boyd R. & Richerson P.J. (1985): Culture and the Evolutionary Process, (Chicago University Press, Chicago).
• Cavalli-Sforza L.L. & Feldman M.W. (1981): Cultural Transmission and Evolution: a quantitative approach, (Princeton University Press, Princeton).
• Csanyi V. (1991): Evolutionary Systems and Society: a general theory, (Duke University Press, Durham, NC).
• Cullen B. (1998): "Parasite Ecology and the Evolution of Religion", in: Heylighen F., Bollen J. & Riegler A. (eds.) (1999): The Evolution of Complexity (Kluwer Academic, Dordrecht).
• Dawkins R. (1976): The Selfish Gene, (Oxford University Press, New York).
• Heylighen F. (1992) : "Selfish
  Memes and the Evolution of Cooperation", Journal of Ideas , Vol.
  2, #4, pp 77-84.
• Heylighen F. (1998): "What makes a meme successful? Selection criteria
  for cultural evolution", in: Proc. 16th Int. Congress on Cybernetics (Association Internat. de Cybernetique, Namur), p. 423-418.
• Lynch, Aaron (1997) "Units, Events, and Dynamics in Memetic Evolution", Journal of Memetics
• Lumsden, Charles, and Wilson, Edward (1981): Genes, Mind, and
  Culture: the Coevolutionary Process, (Harvard University Press,
  Cambridge).
• Moritz E. (1990): "Memetic Science: I - General Introduction", Journal of Ideas 1, p. 1-23
• Moritz E. (1995): Metasystems, Memes and Cybernetic Immortality, in: Heylighen F., Joslyn C. & Turchin V. (eds.), The Quantum of Evolution. Toward a theory of metasystem transitions, (Gordon
  and Breach Science Publishers, New York) (special issue of "World
  Futures: the journal of general evolution, vol. 45, p. 155-171).

See also:

• the electronic Journal of Memetics - Evolutionary Models of Information Transmission.
• an extensive list of web servers on memetics