Ecological risk, demography and technological complexity in the Late Pleistocene of northern Malawi: implications for geographical patterning in the Middle Stone Age JESSICA C. THOMPSON, 1 * ALEXANDER MACKAY, 2 SHEILA NIGHTINGALE, 3 DAVID WRIGHT, 4 JEONG-HEON CHOI, 5 MENNO WELLING, 6,7 HARI BLACKMORE 8 and ELIZABETH GOMANI-CHINDEBVU 9 1 Department of Anthropology, Emory University, Atlanta, GA, USA 2 School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW, Australia 3 Department of Anthropology, City University of New York, Graduate Center, New York, NY, USA 4 Department of Archaeology and Art History, Seoul National University, Seoul, South Korea 5 Department of Earth and Environmental Sciences, Korea Basic Science Institute, Chungbuk, South Korea 6 African Studies Centre Leiden, Leiden University, Leiden, the Netherlands 7 African Heritage Ltd, Zomba, Malawi 8 Division of Archaeology, Department of Archaeology and Anthropology, University of Cambridge, Cambridge, UK 9 Malawi Ministry of Civic Education, Culture, and Community Development, Lilongwe, Malawi Received 15 March 2017; Revised 26 September 2017; Accepted 26 September 2017 ABSTRACT: The Late Pleistocene Middle Stone Age (MSA) record of Africa provides early examples of standardised stone tool production and complex manufacturing sequences, superficially implying a long-term trend towards greater complexity in MSA technology at a continental scale. However, at this scale, spatial and temporal expressions of technological complexity are uneven. New lithic and chronometric data from the East–Central African record add further regional perspective to these patterns. Stone artefact assemblages from Karonga, northern, Malawi (92–22 ka), persistently lack the complexity demonstrated elsewhere in Africa at the same times, despite similar lithic raw materials. These new data provide an essential avenue for exploring hypotheses about the roles of environmental risk and demography in shaping the expression of MSA technology across the continent, not just at a local scale. When set within this framework, the simplicity of the Karonga MSA is best explained by its position in an environment that was persistently low in relative extrinsic subsistence risk. These results reinforce that motivations to invest in complex tools were variable through space and time, and that this variation, more than factors relating to behavioural capacity, may explain the patchy evidence for lithic complexity in the later MSA. Copyright # 2017 John Wiley & Sons, Ltd. KEYWORDS: behavioural adaptations; cultural evolution; Middle Stone Age,; Malawi; stone tools. Introduction The stone artefact record of Africa documents a long history of technological innovation, experimentation, problem-solv- ing and cultural transmission. Within this record, the Middle Stone Age (MSA, from ca. 315 to ca. 30 ka) has received much attention because the material culture associated with it suggests that it was a period that witnessed the origins of modern cultural complexity (Kandel et al., 2016; Wadley, 2015). Although indicators of such complexity become more common towards the end of the Late Pleistocene (124–12 ka), they are not uniformly distributed in time and space across Africa, nor are they uniformly present in most MSA assemb- lages (McBrearty and Brooks, 2000; Conard, 2005; Tryon and Faith, 2013; Soriano, et al., 2015). The patchiness of this early evidence has been used to support a range of quite different proposed cultural trajectories during human behav- ioural evolution, in line with different underlying mecha- nisms. The current state of disagreement suggests that understanding the emergence of complexity requires concur- rent research on the contexts underlying both the appearance and the apparent non-appearance of markers of complexity. We focus here on the evidence for complexity in the most durable realm of human material culture  stone artefacts  in assemblages from the Late Pleistocene of northern Malawi. We then test our observations from that record against expectations derived from some alternative models of cultural evolution and technological change as they potentially relate to geographic and environmental patterning. Nature and limitations of evidence for the evolution of cultural complexity during the MSA in Africa MSA research gained significant traction in the mid-1990s, as researchers began to recognise its potential for offering insight into the origins of ‘behavioural modernity’ (Stewart and Jones, 2016). MSA technologies occur with the earliest evidence of the modern human form (Richter, et al., 2017) and also, apparently somewhat later, co-occur with the full suite of behavioural attributes unique to modern humans. These attributes as expressed in the archaeological record include symbolism, technological complexity, and flexible foraging strategies (Henshilwood and Dubreuil, 2011; Nash, et al., 2013; Van et al., 2013) that are inferred to reflect less tangible attributes such as advanced cognition, hyperprosociality and psychology for social learning (Marean, 2015). Table 1 summarizes selected locations and attributes of directly dated sites containing these inferred indicators. These are mapped in Fig. 1, with proportions of different stone tool types shown  Correspondence: J. C. Thompson, as above. E-mail: jessica.thompson@emory.edu Copyright # 2017 John Wiley & Sons, Ltd. JOURNAL OF QUATERNARY SCIENCE (2017) ISSN 0267-8179. DOI: 10.1002/jqs.3002