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Adze made by a Dani man, Papua, 1970s approximately. Polished greenstone blade in a wooden handle, bound with rattan. Photo: Tracing Patterns Foundation/ Hampton Archive.
In an interesting new paper, Krist Vaelsen and Wybo Houkes (V&H) ask if human culture is characteristically cumulative or not, and more particularly, whether there is evidence for this. A variety of authors, many well-known names, respond:
Is Human Culture Cumulative?
The question might sound like a no-brainer. Surely the evidence of cumulativeness is all around us? Well, yes, but V&H are setting the bar higher. They are asking if cumulativeness is a characteristic of human culture, rather than just an occasional occurrence. This is a good question: for a lot of our history (the longest part, measured in hundreds of thousands of years) stone tool sets did not accumulate innovations. Some of these tools (both flaked and polished stone tools) were still in use in Australasia and the Pacific region in recent times, like the one at the top of this post. They apparently served their makers well.
I will not attempt to summarize all the arguments and counter-arguments, rather I make one general observation about the entire discussion. The naive scholar might get the impression that human culture is (in the first instance) a philosophical topic. The discussion is mainly couched in generalities (both the original paper and the responses). Authors take ‘positions’ on various point of view. There are pleas for more ‘real world datasets’ but little detailed discussion of actual datasets that could answer the questions raised by V&H (Ceri Shipton’s excellent evidence-based discussion of hunter-gatherer toolkits stands out as the exception). The facts discussed are mainly of the ‘stylized’ variety (to use Richerson and Boyd’s expression).
V&H’s excellent questions can be answered to a large extent. Detailed, non-WEIRD studies of human cultural change over a large scale and long time period, spanning the range from simple to complex (the latter characteristic being objectively measurable) do exist. For example:
The Evolution of an Ancient Technology
What are the conclusions? Simply put, V&H are right in one of their key points. Human culture is sometimes cumulative, but not always. Some simple technologies have survived virtually unchanged since Neolithic times (or earlier). Some lineages did accumulate complexity, with demonstrable continuity with the earliest forms. Some lineages even lost complexity. This aspect is driven by other factors (societal, economic), it is not an intrinsic property of cultural change.
Cultural change is a complex empirical question, that can only be answered satisfactorily with high quality data. The kind that takes years of fieldwork and years of coding work to accumulate.
Is Human Culture Cumulative?
The question might sound like a no-brainer. Surely the evidence of cumulativeness is all around us? Well, yes, but V&H are setting the bar higher. They are asking if cumulativeness is a characteristic of human culture, rather than just an occasional occurrence. This is a good question: for a lot of our history (the longest part, measured in hundreds of thousands of years) stone tool sets did not accumulate innovations. Some of these tools (both flaked and polished stone tools) were still in use in Australasia and the Pacific region in recent times, like the one at the top of this post. They apparently served their makers well.
I will not attempt to summarize all the arguments and counter-arguments, rather I make one general observation about the entire discussion. The naive scholar might get the impression that human culture is (in the first instance) a philosophical topic. The discussion is mainly couched in generalities (both the original paper and the responses). Authors take ‘positions’ on various point of view. There are pleas for more ‘real world datasets’ but little detailed discussion of actual datasets that could answer the questions raised by V&H (Ceri Shipton’s excellent evidence-based discussion of hunter-gatherer toolkits stands out as the exception). The facts discussed are mainly of the ‘stylized’ variety (to use Richerson and Boyd’s expression).
V&H’s excellent questions can be answered to a large extent. Detailed, non-WEIRD studies of human cultural change over a large scale and long time period, spanning the range from simple to complex (the latter characteristic being objectively measurable) do exist. For example:
The Evolution of an Ancient Technology
What are the conclusions? Simply put, V&H are right in one of their key points. Human culture is sometimes cumulative, but not always. Some simple technologies have survived virtually unchanged since Neolithic times (or earlier). Some lineages did accumulate complexity, with demonstrable continuity with the earliest forms. Some lineages even lost complexity. This aspect is driven by other factors (societal, economic), it is not an intrinsic property of cultural change.
Cultural change is a complex empirical question, that can only be answered satisfactorily with high quality data. The kind that takes years of fieldwork and years of coding work to accumulate.
Influential authors from Boyd & Richerson to Sperber, careful not to get mired into problems with the analogy, refrained from adopting terms from biological evolution, from ‘adaptative evolution’ to ‘selection pressure’ or ‘mutation’ within the context of cultural evolution, preferring others such as ‘cumulative cultural evolution’ (CCE), ‘bias’ or ‘variation’. However, at the algorithmic level (sensu Marr 1982), cultural and biological evolution are very similar; they are both instances of Complex Adaptive Systems (e.g. Waldrop, 1992; Gell-Mann 1994; Holland, 1996) or, more specifically, of generalised accounts of selection such as Hull’s (1988).
Stasis of a cultural trait does not mean that it is not evolving, or that selection is no longer in operation. Take the ten-thousand-year-old straw basket designs still being used today. These are highly adaptive solutions to a functional niche, in other words they sit at maxima in their adaptive landscape. If their environmental niche (e.g. function, materials available etc) has not changed, selection keeps them where they are. This resembles the case of some organisms (e.g. sulfur bacteria living in a very stable deep-sea ecosystem have not evolved for 2.3 billion years, Schopf et al. 2015). Yet both baskets and sulfur bacteria are adaptive and evolved by selection.
Confusing evolution with increasing complexity plagued biological understanding of Darwinism, but, as per Evolution 101, selection does not equal progress. It equals adaptation, and this may lead evolving traits towards complexity, but also towards simplicity (e.g. Tamariz & Kirby 2015). Note, additionally, that the complexity-simplicity dimension is only one of many (many!) in the adaptive landscape of culture. Nevertheless, the addition of the outputs of evolution—that is, new material or social cultural traditions—constantly change the environment in which culture evolves, they make it ‘bigger’ and more diverse, which generates an increasingly complex environment which affords the evolution of increasingly complex cultural variants. For instance, language affords the evolution of writing, which affords the internet. (The biological implementation of the same algorithmic process can be illustrated by the evolution of new species, which changes the environment and affords the evolution of further species, e.g. plants afford the evolution of plant-eating animals, which afford carnivores etc).
The study of cultural evolution would benefit not only from analysis of new and existing datasets, but from adaptation of concepts from evolutionary biology including, to name but a random few, dominance, development, epistasis, fertilization, linkage, or ploidy and of the formal tools developed to study them. But before the power of those analogies can be fully harnessed, we need a clear mapping of the elements and processes from both biological and cultural implementations to the general evolution algorithmic level. My own proposal for this is in Tamariz (2019).
References
Barton, N., Briggs, D., Eisen, J., Goldstein, D., Patel, N. (2007) Evolution. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press.
Billiard, S., Alvergne, A. (2018) Stochasticity in cultural evolution: a revolution yet to happen. History and Philosophy of the Life Sciences, 40, 9. https://doi.org/10.1007/s40656-017-0173-y
Gell-Mann, M.(1994). The quark and the jaguar: Adventures in the simple and the complex. New York: W. H. Freeman and Company.
Holland, J. H. (1996). Hidden order: how adaptation builds complexity. New York: Addison-Wesley.
Hull, D. L. (1988) Science as a process: an evolutionary account of the social and conceptual development of science. University of Chicago Press.
Marr, D. (1982) Vision: A Computational Investigation into the Human Representation and Processing of Visual Information. Cambridge, MA: The MIT Press.
Schopf, J. William, Anatoliy B. Kudryavtsev, Malcolm R. Walter, Martin J. Van Kranendonk, Kenneth H. Williford, Reinhard Kozdon, John W. Valley, Victor A. Gallardo, Carola Espinoza, and David T. Flannery (2015). Sulfur-cycling fossil bacteria from the 1.8-Ga Duck Creek Formation provide promising evidence of evolution's null hypothesis , Proceedings of the National Academy of Sciences, 112, 2087-2092; www.pnas.org/cgi/doi/10.1073
I agree with your basic point ... culture is a complex adaptive system that shows a wide variety of behaviours, some of which mirror biological systems and some of which do not. Evolution/ selection do not stop, even when some forms appear stable over time.
By the way, you didn't include the references for your own work, eg Tamariz (2019), which sounds interesting.
Chris Buckley
Tamariz, M. (2019) Replication and emergence in cultural transmission, Physics of Life Reviews, 30, 47-71.
https://doi.org/10.1016/j.plrev.2019.04.004
Chris says in this very stimulating post that “the naive scholar might get the impression that human culture is (in the first instance) a philosophical topic. The discussion is mainly couched in generalities (both the original paper and the responses)”.
V&A say in their abstract propose, “A population exhibits CCE if its individuals, across generations, gradually improve their behavior through social transmission of beneficial modifications to the transmitted behaviors.”
The second quote is a good example of the extreme generalities pointed to in the first. I don’t want to repeat arguments I’ve made in the past, I have more specific points to make about Chris’s commentary. I will just repeat Richard Dawkins’ so far unassailed dictum that behaviour is muscle contraction, and muscle contraction alone. This may sound hugely simplistic, but I would add that muscle contraction is the only way anything gets out of a human brain and into the world, and from one human brain to another.
Culture is not mere behaviour, it is behaviour articulated to stuff; and stuff replicated, with an envelope of variation, and selection over time, by behaviour. That is a very simple argument.
The question that Vaesen and Houkes raise is not about culture, it is explicitly and overtly about behaviour, and as Chris and Eric Boudot demonstrate in their exhaustive and definitive The evolution of an Ancient Technology, behaviour, muscle contraction, as in the case of weaving on a loom, is very closely constrained and guided by the loom itself. If you addressed a loom as one conducting an orchestra, textile would not emerge. It is also true that weaving behaviour is guided by “the orientation of older weavers towards detecting and correcting errors (deviations from tradition practice)” and “the codification of complex tasks into ritualized procedures”. Here information is being transmitted from brain to brain, but that information exists, and persists, in compilations of fairly invariant heuristics. A heuristic is a cultural object. The only aspect of a heuristic that is behavioural is the act of transmission, by muscle contraction (vocalisation and gesture), but the heuristic has a durable existence beyond that transient behaviour, otherwise it could not endure. It seems an act of elective hallucination to see accumulation in behaviour, rather than in the heuristic, or more fundamentally in the loom.
I admit absolutely to being Chris’s “naive scholar”, by whom the fundamental question raised by V&H is easily answered. Culture is cumulative, in that it accumulates. The refuse tips of the world testify to this. However Chris employs the term cumulative in a very specific way. He uses the persistence of types, the Acheulian handaxe, Dani Man’s adze, to demonstrate that many types do not accumulate “innovations”. They have achieved homeostasis.
Alex Massoudi points to Hadid T. Nia’s et al The evolution of air resonance power efficiency in the violin and its ancestors as one of the outstanding examples of a material data set. Nia demonstrates that in the 18th C Cremona workshops violins reached a state of perfection through the evolution of, together with much else, their f or sound holes. This was undoubtedly evolution, because it did not proceed from a plan, there was no sequential set of rationalist innovations. Selection was made, according to the sound produced, on a set of contingent variations in sound hole size, shape and spacing, until no further improvement was possible.
Perfection here is not a Platonic ideal. It relates more accurately to the ground covered in Dawkins’ Climbing Mount Improbable and, something which @abenitezburraco tweeted last week, Conrad Waddington’s epigenetic landscape. In both biological and cultural evolution, things, in Dawkins’ metaphor, cannot leap from evolutionary peak to peak, and in Waddington’s (no relation) can only roll down valleys, not up the valley sides. A violin cannot become, in one swift leap, a guitar, nor a guitar a violin. Phylogenies stemming from the Medieval fithele may have branched into other types, but the violin by the 18th C was isolated by being in a valley (or on a peak) and could not escape from the evolutionary process by becoming something else. It was in this sense perfect. All that perfection means is that a Guarneri violin was as good at being a violin as any violin was ever going to be. Within Claudio Tennie’s zone of latent solutions (or as I prefer it, zone of latent potential) all the possibilities along the dimension of “sounding better” had been tried, and the present form, being perfect, became the type. The same goes for Dani Man’s adze and the Acheuli
The same goes for Dani Man’s adze and the Acheulian handaxe. The same goes for the cheetah and the great white shark.
In all these cases the process is evolution, not accumulation. The only possible use of the word accumulation would be to apply it to complexity. The Boeing 747 was an accumulation of around six million separate components, each an evolved type with its own phylogeny. All machines are thus. Such complexity started with articulating just one thing to another, the haft to the blade, the needle to the thong; and has got us to the Jumbo Jet. In this sense you can say the Jumbo Jet is accumulative, just as you could say a cheetah is an accumulation of eukaryotic cells, and eukaryotic cells are themselves in this way accumulative. But I think the question is not whether human culture is cumulative but whether the term, in the context of evolution, has any further use.