Stone Tools and the Evolution of Human Cognition

8: Possible Relations between Language and Technology in Human Evolution

159 ABSTRACT Complex tool use and language are distinguishing characteristics of the human species, yet the existence and nature of evolutionary relations between them remain controversial. Current thinking highlights three possible types of coevolutionary interaction involving shared neural substrates, shared social context, and shared reliance on general capacities. Evidence reviewed here supports the relevance of all three types of interaction and illustrates the contribution that detailed studies of archaeologically visible, technological behaviors, like stone knapping, can make to the study of human cognitive evolution. First, recent functional brain imaging studies of Lower Paleolithic tool making demonstrate an overlap with cortical language circuits that is consistent with motor hypotheses of speech and language origins. Second, ethnographic and developmental evidence highlights the role of joint attention and intentional communication in the social reproduction of both stone knapping and language skills. Finally, growing appreciation of the importance of hierarchical cognition—not simply in language but across domains of human action—is consistent with shared reliance on general information processing capacities. E I G H T Dietrich Stout EMORY UNIVERSITY Possible Relations between Language and Technology in Human Evolution 160 D i e t r i c h S t o u t INTRODUCTION Complex tool use and language are distinguishing characteristics of the human species. For this reason alone, it is tempting to posit evolutionary connections between them. For archaeologists, the possibility that Paleolithic stone tools might shed light on language evolution is even more appealing. But are human language and tool use really related in any more meaningful way than that both are products of an expanded hominin brain (Hewes 1994)? Everyday experience does not suggest obvious links between the two. In fact, stereotypes like the bumbling professor or the hopelessly confusing some-assembly-required instruction manual suggest exactly the opposite. Archaeologists considering this question have similarly posited important differences between language and tool use, including the presence of innate and/or “domain specific” elements in language processing (Wynn 1993) and the absence of language-like syntax and semantics in tool use (Graves 1994). In this view, tool use and language are linked by nothing more specific than a few general cognitive abilities and the overarching context of cultural transmission (Graves 1994; Wynn 1993). Along these lines, it is important to recognize that human language is a complex phenomenon, incorporating a wide array of sensorimotor, conceptual, and grammatical components. It remains controversial which of these might actually be unique to language (Hauser, Chomsky, and Fitch et al. 2002; Pinker and Jackendoff 2005); however, it is clear that many are shared with other behaviors . Working memory, for example, represents a likely point of overlap between language and tool use, insofar as both activities require the construction, production , and analysis of complex sequential action (Gibson 1999; Lieberman 2002; Wynn and Coolidge 2006). Other potentially informative relations arise from the shared social context of human language and technology. Although the apparent innateness of human language acquisition has been cited as an important difference from tool use (Wynn 1993), the relative importance of innate capacities, heritable predispositions , environmental context, and social learning in each case has yet to be fully resolved (Lockman 2000; Pinker 1995; Tomasello 1995). Less controversial is the fact that social interaction plays at least some role in language acquisition , as well as in tool use and the acquisition of complex skills generally. For this reason, species that excel at tool use tend to be those that also possess rich social and communicative repertoires (Emery and Clayton 2004; Reader and Laland 2002). Formal modeling further indicates that selection for increased sociability and/or social learning ability is the most likely consequence of fitness benefits associated with the expression of complex skills (van Schaik and Pradhan 2003). 161 Possible Relations between Language and Technology in Human Evolution In humans, complex skill acquisition is facilitated by cultural learning (Tomasello, Kruger, and Ratner 1993) involving mental state attribution (“theory of mind”) and joint attention. These are, of course, critical components of human linguistic communication in the broad sense (Hauser, Chomsky, and Fitch 2002) and central to the normal course of language acquisition (Carpenter et al. 1998). At the same time, language itself plays an important role in human technological learning and performance, providing a means of directing attention and action during shared activities (Reynolds 1993). This is particularly important in apprenticeship learning, where language can mediate aspects of meaning , motivation, and identity critical to...