Language and labour
Along with language, extensive tool use is one of the defining characteristics of our species. Unlike compositional language, human tool use has clear homologues in our closest relatives. Nonetheless, there are qualitative differences between human and chimpanzee tool traditions. Only humans show cumulative evolution of (tool) culture, i.e. the innovations of one generation not only being transmitted to subsequent generations, but being built upon and refined over time in a way that allows a technological explosion.
Perhaps not surprisingly, philosophers and students of human evolution have long attempted to draw parallels and functional/causal links between the two faculties. One approach, which I term “idealistic”, is to give priority to language and/or abstract reasoning capacities: It was as a consequence of abstract causal representations (that may have been mediated by symbolic thinking or language) that our ancestors could think of and implement complex tools. What I am more interested in this post is the opposite approach, what one might call a materialist approach (a modern incarnation is Embodiment Theory): It is through action, through active tool-aided manipulation of our environments, that we develop such abstract representations in the first place, and to the extent that we do have qualitatively different innate capacities for such representations, those were themselves primarily selected for their role in tool production and use and only then became seconded for other uses, including language.
One way to link the two faculties is functionally. An early example is Frederick Engels, who hypothesized that our enhanced capacities to manipulate the environment, to make it suit our own needs, themselves a consequence of our free hands and tool use, were what made large-scale cooperation and communication adaptive:
Mastery over nature began with the development of the hand, with labour, and widened man’s horizon at every new advance. He was continually discovering new, hitherto unknown properties in natural objects. On the other hand, the development of labour necessarily helped to bring the members of society closer together by increasing cases of mutual support and joint activity, and by making clear the advantage of this joint activity to each individual. In short, men in the making arrived at the point where they had something to say to each other. Necessity created the organ
Similar sentiments can be found in the recent literature, for example when Csibra and Gergely (2009) claim that important aspects of human social and communicative behaviour are an adaptation to the need to efficiently transmit (material) cultural knowledge; or when Sterelny (2012) claims that
hominins were the only primate lineage that evolved language because hominins were the only great apes that evolved as cooperative extractive foragers, simultaneously under selection for enhanced capacities to coordinate, and enhanced capacities to physically manipulate their environment.
Beyond functional links: Formal equivalance?
A much stronger (and still somewhat speculative, as far as I can tell) hypothesis is that language not, or not only, evolved for tool use, but even shares central mechanisms with core aspects of language. Some corroborating evidence comes from the observation that Broca’s area (and its homologue in other primates) is activated in complex motor actions such as those involved in tool use and production (Stout et al. 2008 and references therein, among others). This has lead to the theory that hierarchical (even recursive?) conceptual organisation such as characterises natural language syntax may originate from the domain-extension of a machinery for building conceptual structure that was first fine-tuned in the domain of manual action for the production and use of (meta-) tools. Examples from this line of research include Fitch (2011), who argues for an exaptationist account of the neural substrate of major components of the Faculty of Language, and Pastra and Aloimonos (2012), who attempt to analyse action itself with conceptual tools developed by us syntacticians.
I’m not sure how far this idea can be taken forward, but I certainly find it a very interesting development.
*pan faber is a wordplay on homo faber, “man, the creator” a term used in (philosophical) anthropology to stress the importance of creative, productive activity to human nature and identity.
Csibra, G. and G. Gergely (2011). Natural pedagogy as evolutionary adaptation. Phil. Trans.
R. Soc. B 366, 1149 – 1157.
Fitch, W. Tecumseh (2011): The Evolution of Syntax: An Exaptationist Perspective; Front Evol Neurosci.; 3:9; published online 2011 December 23; doi: 10.3389/fnevo.2011.00009.
Pastra, Katarina and Yiannis Aloimonos, 2012: The minimalist grammar of action;
In: Steele et al. (2012), pp. 103-117; doi:10.1098/rstb.2011.0123
Steele, James, Pier Francesco Ferrari and Leonardo Fogassi (Eds.), 2012: From action to language: comparative perspectives on primate tool use, gesture, and the evolution of human language (theme issue); Phil. Trans. R. Soc. B, January 12, 2012; 367 (1585)
Sterelny, Kim, 2012: Language, gesture, skill: the co-evolutionary foundations of language
Phil. Trans. R. Soc. B August 5, 2012 367 2141-2151; doi:10.1098/rstb.2012.0116
Stout, Dietrich, Nicholas Toth, Kathy Schick, Thierry Chaminade, 2008: Neural correlates of Early Stone Age toolmaking: technology, language and cognition in human evolution; Phil. Trans. R. Soc. B 363(1499): 1939–1949. Published online 2008 February 21. doi: 10.1098/rstb.2008.0001
Stout, Dietrich and Thierry Chaminade, 2012: Stone tools, language and the brain in human evolution. In: Steele et al. (2012), pp. 75-87; doi:10.1098/rstb.2011.0099