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This article appeared in Volume 8 (2) of the Semiotic Review of Books.

SRB Insights: Taking Memes Seriously

by Liane Gabora

Culture as a Second Form of Evolution

While some ideas instantly fade into obscurity, others spread horizontally through society, and vertically from one generation to another, getting progressively refined and embellished along the way. Thus ideas, like the strands of DNA that encode instructions for building and maintaining living organisms, seem to undergo a process analogous to biological evolution.

Accordingly there has been a slow but steady effort to map the concept of evolution onto the dynamics of culture. Popper(72) and Campbell(11) alerted us to the evolutionary flavor of epistemology. Dawkins(17) introduced the notion of a meme -- a replicator of cultural information analogous to the gene. In his words: "Just as genes propagate themselves in the gene pool by leaping from body to body via sperm or eggs, so do memes propagate themselves in the meme pool by leaping from brain to brain." Others have drawn from mathematical models of population genetics and epidemiology to model the spread of ideas (Cavalli-Sforza & Feldman(12), Lumsden & Wilson(56), Schuster & Sigmund(84), Boyd & Richerson(9), Hofbauer & Sigmund(33)).

These works point toward the possibility that memetics constitutes a second form of evolution, distinct from yet intertwined with biological evolution, with the potential to provide the kind of overarching framework for the social and cognitive sciences that the first form provides for the biological sciences. However thus far memetics has not lived up to this potential, a situation that seems unfortunate given the success of the biological precedent. Although much was known about living things before Darwin, his theory of how life evolves through natural selection united previously disparate phenomena and paved the way for further biological inquiry.

Some believe that looking to biological evolution to gain insight into cultural evolution is a waste of time. As Gould(28) put it: "Biological evolution is a bad analog for cultural change... biological evolution is powered by natural selection, cultural evolution by a different set of principles that I understand but dimly." However at an abstract level of analysis they amount to the same thing: exploration and transformation of an information space through variation, selection, and replication. Both present the question of what underlying mechanisms could launch a self-perpetuating adaptive process. Thus the possibility that the two have enough in common that the former can pave the way for the latter seems at least worth pursuing. Skeptics may wonder how we can develop a theory of cultural evolution before we understand how memes are instantiated in the brain. This situation has a precedent: Darwin came up with the theory of biological evolution through natural selection before the discovery of genes. It turned out that genes are laid out in a fairly straightforward way in physical space, which does not appear to be the case with memes. This does not mean they can't evolve, so long as there is a way of retrieving the components of a meme so they can work together as a unit. We may not yet know all the physiological details of how the information manifested in, say, a handshake between two individuals -- with its unique arrangement of contact points, applied forces, and trajectory -- can be traced back to these individuals' mental representations of handshakes, each other, and the situation they are in. But let us proceed with the confidence that a solution exists and can be found.

This paper outlines a theory of how memes evolve, and illustrates how the memetic perspective provides not only a foundation for research into the dynamics of concepts and artifacts at the societal level, but a synthetic framework for understanding how mental representations are generated, organized, stored, retrieved, and expressed at the level of the individual. It also sketches a tentative theory of how an infant develops a sustained train of potentially-creative thought and thus becomes a cog in the meme-evolving machinery. Implications of this theory pertaining to the mechanisms underlying creativity, and why it is virtually nonexistent in other species, are explored. It concludes with discussion of how a cultural-evolution perspective can shape and inspire research in the cognitive and social sciences.

Components of an Evolutionary System

In order for evolution to happen there must be: (1)A pattern of information (a state within a space of possible states). (2)A way to generate variations of the pattern (explore or transform the space). (3)A rationale for selecting variations that are adaptive -- tend to give better performance than their predecessors in the context of some problem or set of constraints (a fitness landscape applied to the space). (4)A way of replicating and transmitting (or amplifying, as molecular biologists refer to it) the selected variations.

In biological evolution, the evolving patterns of information are genes encoded as sequences of nucleotides. Variations arise through mutation and recombination, and natural selection weeds out those that are maladaptive. Replication takes place at the level of the genotype. In cultural evolution, the evolving patterns of information are memes -- mental representations of ideas, behaviors, or other theoretical or imagined constructs, perhaps encoded as patterns of neuron activation. Variations are created by combining, transforming, and reorganizing representations, consciously or unconsciously, or through errors in transmission. Replication is phenotypically mediated; it occurs when representations are transformed into action or language, transmitted through processes such as imitation, and reproduced, more or less, in another brain. Incorporation of these new information patterns into the society alters the selective pressures and constraints exerted by the social environment, which in turn leads to the generation of yet more patterns. Thus memes, like DNA, comprise a self-sustained system for the relentless exploration and transformation of a space of possible patterns.

Culture is Not Just a Predictable Extension of Biological Evolution

The line of reasoning presented here can be succinctly conveyed in terms of information, which is related to the number of differences required to specify the state of a system (Shannon & Weaver(85), Bateson(4)). States have not only a structure of difference relations between them, but also a combinatorial structure -- each state can itself comprise an information space, so that complex information can be built up from simple information. We can rate each state in a space of possible states against some performance measure or fitness criterion and the result is referred to as a fitness landscape, and we can move from one state to another by way of a computation. The world can be viewed as a vast network of computations wherein information is created, transformed, and destroyed. This information often exhibits pattern, or statistical regularity that can be expressed mathematically.

After seeing many shadows cast by the same object we can develop an internal model of what that object looks like without having seen it, and if more than one object is casting shadows we can learn to tell which object is casting any particular shadow. Similarly, by viewing every pattern we encounter as a shadow or footprint of one or more broad causal principles(note 1), we can gain insight into the causal principles that manifest that pattern.

If you were to go back to some time during the first billion years of Earth's history, the only causal principle you would need to invoke to explain pattern in the information present (with the exception of yourself) would be the physical constraints and self-organizing properties of matter.

If you were to go back to some time after the origin of life, approximately three billion years ago, this would no longer be the case. Not that life doesn't exhibit the properties of matter. But it would be virtually impossible for, say, a giraffe to appear in an information space not acted upon by natural selection. Another causal principle -- biological evolution -- would have to beinvoked from this point on.

Today the Earth is embedded with artifacts like computer networks and circuses that cannot be accounted for by appeal to either the properties of matter or biological evolution. That is, biological evolution does not provide us with adequate explanatory power to account for the existence of computers any more than the properties of matter can explain the existence of giraffes. Computers are manifestations of yet another causal principle: the evolution of culture.

Thus pattern in the structure and dynamics of information we encounter in the everyday world can be traced to three broad causal principles -- the physical constraints and self-organizing properties of matter, biological evolution, and cultural evolution. This classification scheme, like all classification schemes, is somewhat arbitrary. There may be subclasses of these principles that deserve to be considered principles unto themselves (note 2), or one could argue that evolution is a self-organizing property of matter, albeit a spectacular one(note 3). The point is: culture is the only process that has arisen since the origin of life that relentlessly exploits the combinatorial potential of information. Despite the fact that culture is grounded in biology (like biology is grounded in the physical constraints and self-organizing properties of matter), the probability of computers arising spontaneously in an information space not acted upon by cultural evolution (like the probability of giraffes arising spontaneously in an information space not acted upon by biological evolution) is vanishingly small. Thus it is inappropriate to dismiss culture as a predictable extension of biological evolution. It is qualitatively different from anything else biology has produced.

Since the machinery that renders cultural evolution -- the human brain -- is a product of biological evolution, much of what is 'out there' can not be cleanly traced to a biological or cultural origin. We will discuss how biology constrains culture through the preferential spread of memes that satisfy biologically-derived needs. It goes the other way too; culture not only affects biological fitness through its effect on behavior (a phenomenon known as the Baldwin Effect) but it dramatically modifies the biological world. Some of the ways in which biological information gets tainted with cultural information seem relatively inconsequential, such as the trimming of hedges, whereas others, such as dog-breeding, have a long-lasting effect. (In fact, one could view dogs as the consequence of a memetic trajectory that was launched by the need to protect property.) Nevertheless, much as it is not imperative to address the role of physical constraints like gravity in studies of, say, embryonic development or squirrel foraging behavior, much can be said about culture without addressing the role of biological constraints.

Taking the Meme-Evolving Apparatus Seriously

The most salient shortcoming of existing models of cultural evolution, and quite possibly the reason they have had relatively little impact, is that although they tell us much about the transmission or characteristics of 'catchy' memes, they fail to adequately address the issue of how novelty is generated. To be of significant theoretical or predictive value memetics must give serious consideration to the processes by which experience in the world turns into new memes in our brains, and address how memetic novelty is expanded further through creative processes. Studies of creativity, on the other hand, have focused on the individual, obscuring the fact that creativity is a collective affair e.g. (Lenat(54), Schank & Leake(82), Mitchell(67), Boden(6)). The ideas and inventions an individual produces build on the ideas and inventions of others (the ratchet effect). Which memes spread and which ones die off reflects the dynamics of the entire society of individuals hosting them.

Thus although at a sufficiently abstract level the notion that culture evolves is obvious, we lack a theoretical framework that bridges transmission studies with studies of creativity, and spells out explicitly how the concept of evolution maps on to the case of culture. To accomplish this we need more than a quick and dirty list of what makes a meme 'catchy'; we have to consider the extent to which it resonates with and enriches the complex web of assumptions, beliefs, motives, and attitudes of its host -- no simple matter. In short, we have to take the meme-evolving apparatus very seriously.

Liane Gabora is at the Center for the Study of Evolution and Origins of Life, University of California at Los Angeles. She is the author of Memes and Variations: a Computational Model of Cultural Evolution (1995), Culture, Evolution and Computation, and "A day in the life of a meme" (1997).

This excerpt is published courtesy of Liane Gabora and the Board of Editors of The Journal of Memetics. The figures in brackets refer to notes and bibliographical references listed at the end of the full article, which can be found at the following WWW address:

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