Contents lists available at ScienceDirect Journal of Anthropological Archaeology journal homepage: www.elsevier.com/locate/jaa Measuring behavioural and cognitive complexity in lithic technology throughout human evolution Antoine Muller a, ⁎ , Chris Clarkson a , Ceri Shipton b a School of Social Science, The University of Queensland, St Lucia, Queensland 4072, Australia b McDonald Institute for Archaeological Research, Downing Street, Cambridge CB2 3ER, UK ARTICLE INFO Keywords: Cognition Knapping experiments Levallois Blade Handaxe Discoidal Bipolar ABSTRACT Stone tool making, observed archaeologically from 3.3 million years ago, involves complex problem solving and forethought, but the relative complexity of different Palaeolithic technologies remains unknown. Decision making in replicative knapping is here used to explore the degree of behavioural and cognitive complexity involved in five different types of stone tool manufacture (bipolar, discoidal, biface, Levallois and prismatic blade) that represent the evolution of core reduction strategies from the Oldowan through to the Upper Palaeolithic. While some hypothesise that each key transition was marked by an increase in cognitive com- plexity, such hypotheses remain untested assumptions. Determining the level of behavioural complexity in- volved in each of these core reduction strategies using problem-solution distance modelling offers a means of detecting significant increases in the level of human cognitive complexity displayed over time. To directly test for differences in complexity among knapping schema, replication experiments were conducted by two highly skilled knappers. Experiments were filmed and the duration of different stages in the sequence was annotated. Hierarchical diagrams were produced showing the organisation of the different actions involved in stone tool knapping. The results show a pattern of increasingly complex behaviour through the sequence of bipolar, dis- coidal, prismatic blade, biface, and Levallois knapping. Neanderthals and their contemporaries, Homo sapiens, employed knapping technologies exhibiting comparably high levels of complexity. 1. Introduction Recognising cognitive and behavioural complexity in the archae- ological record is a key concern in palaeoanthropological research, typically with a focus on such traits as personal adornment, art, pig- ments, complex burials, carved bone, long distance exchange, use of adhesives, and complex projectiles (Henshilwood et al., 2009; Henshilwood and Marean, 2003; Mellars, 1991, 1989a, 1989b; Cain, 2006; Ambrose, 2010, 2001; Foley and Lahr, 1997; Klein, 1995; Marean et al., 2007; Thackeray, 1992; Wadley, 2010; Chase and Dibble, 1987; Milo, 1998; Clark, 1989; Deacon, 1989; McBrearty and Brooks, 2000; Langley et al., 2008). Such items are rare in the archaeological record however, hampering a geographically comprehensive and temporally deep perspective on cognition. The ubiquity of stone tools in the Pa- laeolithic record offers an alternative means of assessing cognitive complexity, but quantifying and comparing lithic behavioural com- plexity remains an elusive goal. This study investigates behaviour and cognition by examining the decision making involved in different types of stone tool manufacture, including bipolar, discoidal, biface, Levallois and prismatic blade core knapping (Fig. 1). These technologies broadly represent the evolution of lithic core technology from the Oldowan (c. 2.6 million years ago) to the Upper Palaeolithic (c. 50 thousand years ago). Behavioural complexity is modelled in this paper via observations and analysis of footage of replicative knapping experiments conducted by two knappers familiar with each reduction strategy. By identifying the minutia of stages involved in these knapping sequences, and ana- lysing these stages through the lens of concepts borrowed from neu- roscience and psychology (discussed further below), the complexity of the decision making processes involved in the manufacture of different stone tools can be reconstructed. Behaviour is defined for the purposes of this paper as the actions undertaken by hominins, while cognition refers to the underlying brain functions that facilitate those actions. To assess the behavioural complexity of different knapping tasks we use problem-solution distance modelling. Problem-solution distance modelling is based on the idea developed by Köhler (1925), that ‘in- direct thinking’ plays a crucial role in complex tasks such as tool making. Indirect thinking involves setting aside an immediate desire or http://dx.doi.org/10.1016/j.jaa.2017.07.006 Received 15 February 2017; Received in revised form 23 June 2017 ⁎ Corresponding author. E-mail address: antoine.muller@uqconnect.edu.au (A. Muller). Journal of Anthropological Archaeology 48 (2017) 166–180 0278-4165/ © 2017 Elsevier Inc. All rights reserved. MARK