Can Cultural Evolution Help Integrate the Social Sciences?

Simply glance at any university’s course offerings and you will notice a puzzling absence—there is not a coherent School of Social Sciences that weaves the many related fields into a unified whole. It is not obvious how psychology relates to sociology, what history has to say about economics, where philosophy fits in with business management, what politics has to do with behavioral science, or what might be the core ideas essential to know about how societies function across time.The lineage of broken social sciences goes quite far back. We can see early signs of division in the 1800’s when religious doctrines gave way to more secular (and thus empirical) approaches to the study of politics, ethics, human behavior, and economics. Each was previously within the domain of moral philosophy. But why did they fail to congeal later like parallel developments in the physical sciences where physics and chemistry became interwoven through frameworks like quantum mechanics, thermodynamics, atomic physics, or the study of fluid mixing processes?This history is richly nuanced and fascinating in its own right, as recent interviews conducted by David Sloan Wilson show for the fields of sociology and anthropology. I won’t go into it here. Instead, I would like to suggest that the time for putting the intellectual Humpty Dumpty back together again has been urgently thrown upon us.There are deeply systemic threats to humanity ranging from things like global warming, rising wealth inequality, the breakdown of trust in societal institutions, rising levels of terrorism and ethnic conflict, and the ascension of authoritarian dictators who bring with them the ominous threat of global war. That should be enough motivation considering that problems like these are deeply interdisciplinary and cannot be solved in a piecemeal manner.Luckily, the synthesis is already begun as this special series in the Social Evolution Forum explores in depth through numerous articles. What I want to focus on here is one especially promising approach to helping the social sciences come together. A book published in 2011 by Alex Mesoudi, Cultural Evolution: How Darwinian Theory Can Explain Human Culture & Synthesize the Social Sciences, takes Darwin’s method as its central thesis.Stated succinctly on its back cover:

“Charles Darwin changed the course of scientific thinking by showing how evolution accounts for the stunning diversity and biological complexity of life on earth. Recently, there has also been increased interest in the social sciences in how Darwinian theory can explain human culture.”

The book looks at the earliest attempt to apply scientific concepts about evolution to human culture—in Darwin’s 1871 book The Descent of Man that created a great deal of controversy by comparing languages to phylogenetic trees of different species and generally considering humans to be part of the natural world. Flash forward a century and we see that Edward O. Wilson’s attempt to bring humans into a scientific framework informed by biology (in his 1975 book Sociobiology: The New Synthesis) was highly praised for making sense of social behaviors across the animal kingdom, yet provoked harsh criticism for its final chapter where the same analysis was applied to human beings.Mesoudi starts off by explaining how “methodological individualism” plagues many of the social sciences. The majority of psychologists and cognitive scientists are blinded to the influences of culture by exclusively focusing on what happens inside the individual mind. Economists too are prone in their mathematical modeling to treat market actors as rational individuals without taking account of social norms, institutional practices, and other cultural factors. This reductionism that removes individuals from their social context is addressed by other social scientists (for example sociologists who explore leadership norms, anthropologists who make cross-cultural comparisons of ritual practices, or historians who treat economies as complex adaptive systems) but the bridges have not yet been built across these research explorations in a consistent or systematic manner.His book then strips Darwin’s approach down to three essential concepts: variation, competition, and inheritance. If one can show that human cultures always exhibit these features, it becomes possible to discover how social change functions according to general principles that map across different academic disciplines.The book goes through chapter by chapter showing how this is already being done. One illustrative example is the work of Michael O’Brien and his collaborators. They introduced the biological tools for creating phylogenetic trees to the design of spear tips uncovered at archeological sites in the Southeastern United States. This enabled them to explore how ideas spread from one community to another using physical artifacts as the “cultural fossils” that evolved across time.

As the image to the right shows with stark clarity, the different spear shapes fell into distinct lineages showing patterns that are familiar to biologists like convergent evolution (similar structures arising in separate contexts where the environments have factors in common) and the uncovering of “clades” or ancestral family lines. More significantly, they were able to explore questions about knowledge diffusion that would have been impossible without employing phylogenetic analysis. For example, the black and white squares in this image represent different developmental pathways for the evolution of hunting technology.Some spears were re-invented in multiple locations. Others spread by social learning between communities. As none of these cultural patterns left a physical record on its own, they would not have been tractable without taking account of the evolutionary pathways revealed by analysis of this kind.This begs the question of “over fitting” to theoretical models. Might it be the case that the spear tips fell into a statistical pattern of descent-with-modification that was spurious? Mesoudi addresses this important challenge by showing how other researchers have created control experiments to measure the efficacy of phylogenetics for cultural data.One validation for approaches like this is the study of transcription error for famous literary manuscripts. Before the invention of the printing press it was necessary for scribes to create new versions of a text by hand. This naturally led to errors that can be traced if the detailed history is known for all versions that were written out. Such a database was created by humanities scholars, enabling Michael Spencer and colleagues to compare phylogenetic analysis with the historic record.

The image to the right shows how well it worked. The graph labeled (a) is drawn from a historic dataset with full knowledge of dates and transmission pathways. Graph (b) was created using phylogeny showing that it recovered the structures and timelines with high fidelity.What studies like these show is that research tools from biology can inform (and in some cases, improve upon) methods from the social sciences and humanities. Mesoudi goes through many more examples like these to make a compelling case for Darwinian evolution to be a powerful framework for knowledge synthesis across disciplinary boundaries.But what about the entire knowledge ecology of the social sciences? Surely cultural evolution is inadequate for capturing the broad features of what has been learned in so many different fields, right? Mesoudi attempts to address this by zooming out to see how evolution has been able to create such vast cohesion across all of the biological domains—from the tiniest genetic markers up through vast geologic epochs of living systems.

As this figure from his closing chapter conveys, one can attempt a formal translation of knowledge structures from biology to the social sciences writ large. Doing so reveals a coherence across the many ways that culture is already studied that can be elaborated and clarified intentionally once it is recognized.For example, biology has separate efforts to conduct experimental studies of population genetics that inform (and are informed by) parallel efforts to run mathematical models of theoretical interest. Mapped to the social sciences, we can see how psychological experiments inform (and may be informed by) modeling efforts that explore how cultural traits are transmitted across a population of people. Powerful tools for doing this were developed in the 1970’s and 80’s by researchers like Marcus Feldman, Luigi Cavalli-Sforza, Robert Boyd, and Peter Richerson (see here and here for two foundational texts).Similarly, the various studies in population ecology for biologists can be mapped to large-scale social studies like those conducted by historians and economists. Great strides have been made here in recent years as well. Simply grab a copy of Complexity and Evolution: Toward A New Synthesis for Economics or peruse the more accessible popular articles in Evonomics magazine. Or join the Seshat World History Databank project that is applying tools from population dynamics to the rise and fall of civilizations.What I found most compelling in Mesoudi’s book is what has transpired since he wrote it six years ago. In 2015 an effort was launched to birth a scientific society for the study of cultural evolution. A survey sent out to its first 1000 founding members revealed knowledge synthesis as the most important “grand challenge” for the field. The findings were just reported here in the journal Nature Ecology & Evolution.There is a real hunger for putting the Humpty Dumpty together in the early 21^st Century as the Cultural Evolution Society makes its mission to promote the synthesis of biology, the social sciences, and humanities. More than 1700 researchers from 50 countries have signed onto this effort so far—with plans for the first international conference in September later this year.My only complaint about Mesoudi’s book is that I see a broader set of frameworks being vital to this effort than Darwinian evolution on its own. In another essay, I suggested that meme theory can be updated by incorporating advances from complexity science, cognitive linguistics, and the social analytics of digitized datasets. The real power for bringing cohesion to the social sciences will be to take another idea popularized by E.O. Wilson—that of consilience or the convergence of methods, findings, and theoretical insights across diverse scholarly inquiries.To demonstrate the power of consilience, consider what becomes possible if we combine what Mesoudi has shown for Darwinian evolution as a “great synthesizer” for knowledge with two other frameworks: embodiment philosophy and the study of complexity.The Theory of Embodiment is beautifully laid out in the works of Francisco Varela and Humberto Maturana, George Lakoff and Mark Johnson, Raymond Gibbs, and more recently Andreas Weber. It’s central tenet is that human minds (and those of all other living things) arise as a complex interplay of brain, body, and environment. This philosophical position has enabled cognitive scientists to make huge interdisciplinary advances in the last half-century.Complexity was already mentioned as an approach to the study of history and economics. Here I refer to the corpus of work that can be broadly extended from the Santa Fe Institute—with the study of chaotic attractors, phase transitions, the science of emergence, symmetry breaking, and more. The tools of analysis for non-linear dynamic systems can greatly inform (and already are) how the social sciences get practiced. Indeed, they already are as this "before and after" study of the recent Arab Spring uprisings shows.If we combine evolution with embodiment and complexity (plus other frameworks that could also be mentioned), a coherent School of Social Sciences feels very much within reach. It may take a few decades to evolve our academic institutions to reflect this kind of holistic integration. Yet, as I have attempted to show here, such a project is aligned with where many scholarly fields are already heading.In answer to the question that titles this thought piece, I offer the affirmative. Cultural evolution can help integrate the social sciences. And the world is calling us to this important work as we grapple with a host of deep systemic challenges in the 21^st Century.