re: Adventure Memes/Duration Memes

Aaron Lynch (
Thu, 28 May 1998 10:27:12 -0500

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Date: Thu, 28 May 1998 10:27:12 -0500
From: Aaron Lynch <>
Subject: re: Adventure Memes/Duration Memes
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I'm not sure that Karthik was really trying to identify the
epidemic/endemic distinction. In the case of early Christianity, the meme
set doubled at a rate of about once per 20 years over a course of centuries
until it was endemic in the Roman empire. (Stark, 1996) During those early
centuries, it was essentially a slow-motion epidemic, but it would qualify
as a "duration meme" in Karthik's terminology because of its evolved
mechanisms for long-term preservation of belief. Similar slow-motion
epidemics are currently in progress, such as Mormonism (e.g., Lynch, 1996).

For mathematical models, what we really need are unified theories that do
not care whether a meme is epidemic, endemic, or in between these
conditions. Building memetic equations directly from memetic event rate
parameters rather than by attempting to identify isomorphisms to work done
for other infectious agents strikes me as the surest path to take, since
this work is required in demonstrating an isomorphism anyway. I have
presented equations that take account of vertical (parent to child) and
horizontal (peer to peer) transmission events, as well as dropout and
mortality events, in my recent paper at JOM-EMIT (Lynch, 1998). This
provides a method that can be expanded to applications where more specific
event types are identified and quantified. These equations apply equally
well whether propagation is in an epidemic or endemic phase.

Lynch, A. 1996. Thought Contagion: How Belief Spreads Through Society. New
York: Basic Books.
Lynch, A. 1998. Units, Events, and Dynamics in Memetic Evolution. Journal
of Memetics 2, #1,
Stark, R. 1996. The Rise of Christianity. Princeton: Princeton University

>If I interpret you correctly, the distinction you make between
>adventure memes and duration memes is essentially the same as
>Sperber (1985) makes between what he calls 'epidemic and endemic
>Sperber writes (1985, p.74):
>'For instance, a representation can be cultural in different ways:
>some are slowly transmitted over generations; they are what we
>call traditions and are comparable to endemics; other
>representations, typical of modern cultures, spread rapidly
>through a whole population but have a short life-span; they are
>what we call fashions and are comparable to epidemics.'
>The use of epidemic modelling in what we would now call memetics
>(although of course it wasn't in those days), dates back I think
>to the work of Rashevsky in the early 50s. There was a whole glut
>of papers in a journal called Bulletin of Mathematical Biophysics
>(I am still chasing them up), on epidemiological models of
>cultural change. For example Rashevsky N. (1949) Mathematical
>biology of social behaviour I. Bull. Math. Biophys. 11, 105-113.
>This is epidemic modelling, and there are no shortage of current
>epidemic models. For endemic modelling (your duration memes) we
>have to turn to Cavalli-Sforza and Feldman (1981, p.53) who write:
>'The theory of endemics is still in its infancy. It may be of
>importance for....improving our understanding of the maintenance
>of social customs and habits that are...present over long periods
>of time.'
>Cavalli-Sforza and Feldman suggest an adaptation of the endemic
>model of Dietz (this is 1972, but in a rather difficult-to-find
>book - in any case it is given in Cavalli-Sforza and Feldman p.
>51. equ. 1.10.6)
>Just how 'endemic' some socieities are (in your terms how much of
>our cultural baggage is durational rather than adventurous) can be
>seen by a glance at Hewlett and Cavalli-Sforza's (1983) analysis
>of the Aka pygmies. Virtually every cultural trait (ie. meme, if
>you agree on the correspondence) that they examine is known to
>upwards of 90% of the population. The only exceptions are cooking
>skills which are only known to 46.7% of adult males (vs. all adult
>females) and hunting skills which are only known to 77.5% of adult
>females (vs. 100% of adult males) Helwett and Cavalli-Sforza
>(1983, p.931)
>In fact. the only convincing demonstration that these authors make
>of a recent cultural 'epidemic' is the change from bow-and-arrow
>to crossbow in hunting. This spread recently and rapidly through
>the whole population (possibly due to the selective advantage it
>gives to hunting ability).
>Cavalli-Sforza LL and Feldman MW (1981) Cultural Transmission and
>Evolution. Princeton University Press.
>Hewlett BS and Cavalli-Sforza LL (1983) Cultural transmission
>among Aka pygmies. American Anthropologist 88, 922-934.
>Sperber D (1985) Anthropology and psychology: towards an
>epidemiology of representations. Man 20, 73-89.
>Hope this helps.
>Derek Gatherer

--Aaron Lynch

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