Part One of a multi-blog piece.

Note: For a more dynamic presentation of these ideas in which everything is explained with images and animation, see: https://www.youtube.com/watch?v=VExITmJUjUA For a more in-depth explanation, see (Gabora, 2004, 2011, 2013), or my book Dawn of the Creative Mind: The Origin and Evolution of Culture and Innovation, forthcoming from Cambridge University Press.

For well over a century, Darwin’s theory of natural selection has served as biology’s grand unifying framework, explaining how species adapt and evolve through the differential reproduction of randomly generated variations. Given its success in biology, it’s natural to wonder whether this framework might explain another kind of evolution we see all around us: That of human culture. A scientific framework for cultural evolution could integrate the social sciences under one explanatory umbrella, as natural selection did for the life sciences. It could help us understand how we got here, who we are, and where we’re headed. It might help us document human civilization, or be used to mine trends or analyze gaps in technological change, and shed light on what factors lead to ground-breaking innovations.

Culture Does Evolve

Cultural innovations such as technologies, artistic styles, and social practices build on earlier ones and tend to benefit their bearers and become more useful over time. This kind of cumulative, adaptive change was demonstrated in a computer model of cultural evolution in which neural network-based agents creatively invent new actions and imitate their neighbours (Gabora, 1995). Thus, it’s uncontroversial that culture exhibits cumulative, adaptive change; it evolves. The question is: How? What kind of scientific framework can accommodate it?

The computer model of cultural evolution showed phenomena typical of biological evolution, such as drift (fixation on one trait despite that others are equally fit due to random fluctuation in trait frequencies), and epistasis (where the effect of one trait depends on another). This suggests it’s worth investigating the possibility that natural selection, the theory designed to explain how organisms evolve, can also explain how culture evolves.

Culture Doesn’t Have the Problem Darwin’s Theory Was Designed to Solve

To assess this, we can look at what problem Darwin’s theory was designed to solve, and whether culture faces the same problem. Darwin observed that living organisms are exquisitely adapted to their environments. For example, the finches on different Galápagos Islands have beaks perfectly suited to their local food sources. Moreover, these adaptations accumulate gradually over time, as evidenced by the gradation of beak shapes across related species.

However, the traits that organisms acquire during their lifetimes aren’t transmitted to their offspring. If you get a tattoo or a degree in geology, your child isn’t born with a tattoo or knowledge of geology. This creates a paradox: If each generation’s acquired adaptations are discarded, how do species become increasingly well-adapted over time?

Darwin’s genius was to shift the focus from individuals to populations. He realized there are two kinds of transmission: traits that are acquired over a lifetime (like a tattoo), and traits that are inherited (like eye colour). Though acquired traits disappear each generation, inherited traits are transmitted to offspring (in what we now call DNA). He realized that these inherited traits undergo random variations, and variations that improve an organism’s ability to survive and reproduce are more reliably passed on to offspring. They thereby become more common in subsequent generations. This is natural selection: Cumulative, adaptive change through differential reproduction of randomly generated heritable variations. In this way, Darwin explained how adaptive change is retained despite that acquired traits aren’t transmitted.

Culture doesn’t face the problem Darwin’s theory was designed to solve, the problem of how change accumulates despite acquired changes getting obliterated each generation. Once someone invents a teapot handle, teapots could thereafter have handles. If we try to apply natural selection to culture, we’re trying to use a framework specifically designed to explain evolution in systems where acquired traits aren’t transmitted, to explain evolution in a system where they are.

Culture Doesn’t Possess the Algorithmic Structure of Natural Selection

John von Neumann (1966) later showed that the minimal structure capable of evolving through natural selection is a self-replicating automaton: a set of instructions that, if followed, produce a copy of the instruction set itself—a self-assembly code. This self-assembly code must serve two functions. First, it is passively copied during *reproduction *to produce gametes: sperm and egg cells that join to form a zygote, the starting point of a new organism. Second, the self-assembly code is actively interpreted during *development *to turn this zygote into a functioning organism. Changes acquired by the organism are shielded from gametes (the “Weismann barrier”), thus, not inherited.

However, unlike biological organisms, cultural units aren’t self-replicating automata. A hammer or a painting doesn’t autonomously make copies of itself. No self-assembly code is interpreted during development and passively copied during reproduction.

Dawkins** **claimed that cultural units, like genes, are replicators. He defined a *replicator *as “any entity in the universe which interacts with its world, including other replicators, in such a way that copies of itself are made.” However, the replicator concept doesn’t capture the algorithmic structure of a self-replicating automaton: the minimal entity that can evolve through natural selection. Moreover, it lacks the signature feature of natural selection: the lack of transmission of acquired traits.

Only One Form of Inheritance

Dual inheritance theory, the idea that culture is a “second system of inheritance” (Boyd and Richerson, 1978; Henrich and McElreath, 2007), is profoundly misleading. In biological inheritance, offspring receive genetic information for traits that may never have been expressed in their parents. For example, even if your parents never break a bone, and the genes for bone repair never turn on in their lifetimes, you still inherit those genes, and they still work fine if *you *break a bone. In contrast, if your parents know how to ice fish but never teach you, you don’t have that knowledge. That’s because the knowledge of ice-fishing, like all cultural information, is acquired, not inherited. We have two systems of transmission, but just one system of inheritance.

References

See a dynamic presentation of these ideas in which everything is explained with images and animation. For a more in-depth explanation, see (Gabora, 2004, 2011, 2013), or my book Dawn of the Creative Mind: The Origin and Evolution of Culture and Innovation, forthcoming from Cambridge University Press.

Dawkins, R. (1975). The selfish gene. Oxford: Oxford University Press.

Gabora, L. (1995). Meme and variations: A computational model of cultural evolution. *1993 Lectures in complex systems, *471–485. Addison Wesley.

Gabora, L. (2004). Ideas are not replicators but minds are. Biology & Philosophy, 19(1), 127-143.

Gabora, L. (2008a). Modeling cultural dynamics. *Proceedings of the Association for the Advancement of Artificial Intelligence (AAAI) Fall Symposium 1: Adaptive Agents in a Cultural Context *(pp. 18-25). Menlo Park, CA: AAAI Press.

Gabora, L. (2008b). EVOC: A computer model of the evolution of culture. In V. Sloutsky, B. Love & K. McRae (Eds.), 30th Annual Meeting of the Cognitive Science Society (pp. 1466-1471). North Salt Lake, UT: Sheridan Publishing.

Gabora, L. (2011). Five clarifications about cultural evolution. Journal of Cognition and Culture, 11, 61-83.

Gabora, L. (2013). An evolutionary framework for culture: Selectionism versus communal exchange. Physics of Life Reviews, 10(2), 117-145.

Henrich, J., & McElreath, R. (2007). Dual-inheritance theory: The evolution of human cultural capacities and cultural evolution. In R. I. M. Dunbar & L. Barrett (Eds.),Oxford handbook of evolutionary psychology (pp. 555–570). Oxford University Press.

Richerson, P. J., & Boyd, R. (1978). A dual inheritance model of the human evolutionary process I: Basic postulates and a simple model. Journal of Social and Biological Structures, 1(2), 127-154.

Von Neumann, J. (1966). Theory of self-replicating automata. University of Illinois Press.