Daniel Nettle recently uploaded a preprint of an article to be published in Philosophical Transactions of the Royal Society, B: Selection, adaptation, inheritance and design in human culture: The view from the Price equation (PDF). He argues that the dual inheritance theory of cultural evolution is in trouble. Here’s the abstract:
For decades, parts of the literature on human culture have been gripped by an analogy: culture changes in a way that is substantially isomorphic to genetic evolution. This leads to a number of sub- claims: that design-like properties in cultural traditions should be explained in a parallel way to the design-like features of organisms, namely with reference to selection; that culture is a system of inheritance; and that cultural evolutionary processes can produce adaptation in the genetic sense. The Price equation provides a minimal description of any evolutionary system, and a method for identifying the action of selection. As such, it helps clarify some of these claims about culture conceptually. Looking closely through the lens of the Price equation, the differences between genes and culture come into sharp relief. Culture is only a system of inheritance metaphorically, or as an idealization, and the idealization may lead us to overlook causally important features of how cultural influence works. Design-like properties in cultural system may owe more to transmission biases than to cultural selection. Where culture enhances genetic fitness, it is ambiguous whether what is doing the work is cultural transmission, or just the genetically-evolved properties of the mind. I conclude that there are costs to trying to press culture into a template based on Darwinian evolution, even if one broadens the definition of ‘Darwinian’.
For the full argument I urge you to read the article itself. I’m not going to attempt to summarize or paraphrase it here.
Why not?
Because it doesn’t apply to the account of cultural evolution that I espouse.
Dual inheritance theory (kin to gene-culture coevolution) sees culture as directly benefitting genetic fitness. I don’t think that’s how culture words works. Biological evolution is about bodies. Cultural evolution is about minds. And yes, the mind is what the brain does and so the mind can never be free of the body. Ultimately, the cultural development of minds must at the very least not harm the biological integrity of bodies. But, over the long term, minds can evolve independently of bodies and that is what we see in the history of human societies. Brains are much the same everywhere, but cultures differ and so, I argue, do the minds that support those cultures.
Later in the article Nettle indicates the possibility of a fundamentally different conception of the relationship between culture and biology, but he does not explore it:
Even if the move from people to song renditions as the Darwinian individuals proved fruitful, it would still be wrong to claim that humans have a second system of inheritance running alongside the genetic one, or a dual inheritance. In the rendition-as-individual idealization, humans are not inheritors of culture. They are just the ecological background, providing selection pressures on cultural renditions through their tastes and propensities. We can retain the notion that humans are the individuals whose phenotypes we are studying, but in this case, we must recognize that their acquisition of culture is not like the inheritance of their genes, and so they only have a dual inheritance as a metaphor or idealization. Alternatively, we can move to modelling a world where humans, one type of Darwinian individual evolving with one system of inheritance (genes), are hosts and ecological backgrounds to the propagation of another type of Darwinian individual (song renditions), which also has one system of inheritance.
That is, in effect, what Dawkins had in mind when it posited the existence of cultural memes late in The Selfish Gene. It was the meme, which he conceived as the cultural equivalent of the biological gene, that directly benefitted from cultural evolution, not the people who provided the ecology in which those memes function.
That is the position that I have been developing over the years. I have dropped the term “meme”, both because of the baggage it has accumulated over the years, but also because I don’t think it captures the central notion, which is that of coordination (see annotated references below). The function of these coordinators, as I have called them is to facilitate the performance of complex activities among interacting individuals, initially in direct face-to-face interaction, either in dyads or in small groups of various sizes.
I have taken music as my paradigm example (see Beethoven’s Anvil, and “Rhythm Changes” below). Coordinators are those features of public objects or events which have been encoded as culturally significant. In the case of music, the most basic coordinator is the foundation beat of the music. Everyone making music together must agree on and adhere to that beat.
In this conception the Darwinian event is the performance itself. If a performance is pleasing, the musicians will be motivated to repeat it on a later occasion. Otherwise, not.
Beyond this, well, it’s complicated. Details are available in the publications I’ve listed below.
Finally, I note that in this conception change over time is not the focus of the cultural recasting of the gene/phenotype mechanism. The focus is stable, well-coordinated, intelligible interaction action among individuals. Where the interaction involves adults and children the mechanism will take care of inheritance from one generation to another. If things change over time, for whatever reason, that is a side-effect of the mechanism, albeit a very interesting and enormously important side effect.
Annotated References
William Benzon, Culture as an Evolutionary Arena, Journal of Social and Evolutionary Systems 19 (4): 321-362, 1996, https://www.academia.edu/235113/Culture_as_an_Evolutionary_Arena
William Benzon, Beethoven’s Anvil: Music in Mind and Culture, Basic Books, 2001. Final drafts of chapters 2 and 3 can be downloaded from the web, https://www.academia.edu/232642/Beethovens_Anvil_Music_in_Mind_and_Culture. In this chapters I argue that the coordination between people making music together is so very close that we may consider their nervous systems to be coupled together into a single system in which some signals pass internally within brains while others pass externally through the air in the form of sound waves. Later in the book I argue that the collective neural trajectories of such performances constitute the cultural equivalent of the biological phenotype (pp. 191-193, 219-221). If we think of the collective neural system of the group as a complex dynamical system, then the performance trajectory is an attractor in that system.
Note that, while Dan Sperber published his initial account of cultural attraction in Explaining Culture: A Naturalistic Approach (1996) before I’d even begun to work on Beethoven’s Anvil, I was unaware of it at the time. I have my conception of complex dynamics from various sources, but particularly from the work of the late Walter Freeman on the nervous system. In Sperber’s conception the elements in the system are variants of some cultural object. In my conception the elements of the system the neurons in the brains of the people performing music together (my paradigm case). These neurons, of course, exist in huge interconnected bundles, one bundle for each individual involved in the performance. The role of those coordinators, then, is to allow those different bundles to function as a single system.
The problem arises, then, of how to generalize from that very specific situation, which is common enough in hunter-gatherer bands, to different kinds of practice, such as speaking or basket weaving, and to very different socio-cultural circumstances. One cannot just say, I generalize thus. One must provide specific constructions. That is a challenge. And it is a feature of this conception, not a bug.
William Benzon, The Evolution of Human Culture: Some Notes Prepared for the National Humanities Center (Version 2), Working Paper, October 13, 2014, https://www.academia.edu/8748485/The_Evolution_of_Human_Culture_Some_Notes_Prepared_for_the_National_Humanities_Center_Version_2_. Among other things, this working paper contains early drafts of the material I used in the “Rhythm Changes” article and I has some suggestions about how to generalize the conception from music to language.
William Benzon, “Rhythm Changes” Notes on Some Genetic Elements in Musical Culture, Signata 6, Annales des Sémiotiques /Annals of Semiotics: Sémiotique de la musique / Music and Meaning. Per Aage Brandt and José Roberto do Carmo Jr., eds. Presses Universitaires Liège, 2015, pp. 271-285, http://www.academia.edu/23287434/_Rhythm_Changes_Notes_on_Some_Genetic_Elements_in_Musical_Culture. I consider a specific complex example of musical coordinator, the chord changes from the tune “I Got Rhythm”, and has some remarks about the evolution of those changes into an independent entity in the musical culture of jazz.
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