Gene-culture co-evolution
In this final lecture, I am going to talk about gene-culture co-evolution, and how it relates to language. The reading for this week is Smith (2020), which is a review paper I wrote with this lecture in mind! It returns to a number of themes we have seen in this course, including cultural evolution as a mechanism generating language structure and the cognitive capacities required for cultural transmission, and introduces some new stuff on gene-culture co-evolution for language. This blog provides some more general context on gene-culture co-evolution.
The main idea behind gene-culture coevolution is that genetic and cultural evolution interact with each other: culturally-transmitted behaviours (like farming, tool use, urban living or language) create selection pressures which drive genetic evolution, and that genetic evolution sets the scene for further cultural evolution. We already came across this idea in relation to the Morgan et al. (2015) paper on the co-evolution of language and tool use. The idea in that paper is that the use of stone tools (a socially-learned behaviour) generated a selection pressure for enhanced social learning or language abilities, because these abilities facilitated the learning and transmission of stone tool technologies, and individuals with better learning/language abilities learned these survival-critical skills faster and/or were more successful at passing those skills on to their offspring. Given this selection pressure created by the cultural practice of tool-making, natural selection responds by selecting for genes which produced individuals with improved social learning/communicative abilities; the enhanced learning/communicative abilities produced by natural selection then set the stage for the development of more complex technologies (again via social learning), which in turn increased the selection pressure for genes encoding more sophisticated learning/language abilities, and so on in a repeated cycle of more complex technologies and genes better adapted to those more complex technological environments. This is a classic (hypothetical) case of gene-culture co-evolution: genetic and cultural evolution feed back on one another, each driving on changes in the other.
While this case involving language is rather speculative, there are a number of better-evidenced cases of gene-culture co-evolution, including classic work on how the cultural practice of dairying generates selection pressure for genes allowing individuals to consume milk into adulthood, and how cooking might have changed selection pressures on human facial musculature (basically if you cook your food you don’t need to chew it as much). You can read this American Scientist article for a nice non-technical summary of some similar findings.
For me, the most exciting idea in the gene-culture co-evolution literature is that humans have undergone rapid evolution in the recent past (and therefore probably in the present day), as a result of environments we ourselves have created through culturally-transmitted behaviours including agriculture, our social systems, and maybe language. I think a lot of people have the intuition that genetic evolution is basically finished in humans, because we can insulate ourselves from the environment through culturally-transmitted skills, behaviours and technologies (sometimes called counteractive niche construction); but the exciting thing is that exactly the same processes generate new selection pressures, as we create new environments which our must genes adapt to (sometimes called inceptive niche construction).
Smith, K. (2020). How culture and biology interact to shape language and the language faculty. Topics in Cognitive Science, 12, 690-712. https://doi.org/10.1111/tops.12377
Morgan, T. J. H., Uomini, N. T., Rendell, L. E., Chouinard-Thuly, L., Street, S. E., Lewis, H. M., Cross, C. P., Evans, C., Kearney, R., de la Torre, I., Whiten, A. & Laland, K. N. (2015). Experimental evidence for the co-evolution of hominin tool-making teaching and language. Nature Communications, 6, 6029.
All aspects of this work are licensed under a Creative Commons Attribution 4.0 International License.