1 Hominin Tool Evolution and Its (Surprising) Relation to Language Origins 1 Ronald J. Planer a,b , Elisa Bandini c, and Claudio Tennie d 2 a. School of Liberal Arts, University of Wollongong, Australia. 3 b. Words, Bones, Genes, and Tools: DFG Center for Advanced Studies, University of Tübingen, Germany 4 c. Department of Evolutionary Biology and Environmental Studies, University of Zürich, Switzerland 5 d. Faculty of Science, Department of Geosciences, Working Group Early Prehistory and Quaternary Ecology, 6 University of Tübingen, Germany 7 To appear in The Oxford Handbook of Approaches to Language Evolution 8 Abstract: Culture and communication are widespread in the animal kingdom. However, among 9 apes, only the human line has evolved these into something altogether different. Moreover, our 10 extraordinary cultural and communicative capacities underlie much else of what makes our 11 species stand out among apes. Thus, understanding the how and why of the process by which 12 these capacities were transformed from their great ape-like precursors into their modern 13 human equivalents is of fundamental importance to the challenge of understanding the 14 evolution of our species more generally. In this chapter, we take up these questions using a 15 novel framework for thinking about social learning. We hypothesize that human apes show a 16 unique propensity for a certain type of social learning, which we call “know-how copying.” 17 Know-how copying is considered foundational to our species’ well-known capacity to culturally 18 evolve both behaviour and artifact forms that can far exceed anything a single individual could 19 realistically invent on his or her own. This copying is therefore also foundational to our species’ 20 capacity to construct, maintain and expand the large lexicons of (often) arbitrary signs that 21 underlie human languages. After discussing the various methodologies that are available for 22 testing whether a given type of human or animal culture is demanding of know-how copying, we 23 turn to the archaeological record with an eye towards identifying plausible signatures of the 24 origins of know-how copying in the human line. In particular, we examine the course of hominin 25 technological evolution – as the most visible and most frequent data. We suggest a much later 26 date for the origins of know-how copying than is typically assumed. But this poses a deep 27 puzzle, namely: there is good reason to think that hominins had considerably expanded their 28 communicative repertoire prior to the evolution of know-how copying. How was this possible in 29 the seeming absence of know-how copying? We sketch a solution to this puzzle which we think 30 provides an additional argument in support of a gestural-iconic origins scenario for language. 31 Keywords: social learning; cultural evolution; know-how copying; method of local restriction; 32 Oldowan; Acheulean; Homo erectus; gestural origins of language 33 34 1. Introduction: Varieties of Cultural Learning 35 It’s now widely agreed that humans’ cultural capacities were a crucial evolutionary driver of our 36 species’ unique success.. However, it’s also agreed that many other species have culture (e.g. van 37 Schaik, 2010). Yet, the key differences between the cultural capacities of humans and other 38 animals remains hotly disputed territory. Rather than focus on the controversies, our goal in 39 this chapter is to set out a novel social learning framework (Bandini and Tennie 2018; Bandini 40 et al. 2020), along with a working hypothesis within this framework. We then use this 41 framework and hypothesis to explore a major unresolved issue in the evolution of language, 42 namely, the modality and type of the very earliest forms of language—we think, with some 43 surprises. 44