Langley Michelle (Orcid ID: 0000-0002-0299-5561) Mobile Containers in Human Cognitive Evolution Studies: Understudied and Underrepresented Michelle C. Langley & Thomas Suddendorf Issues Essay for Evolutionary Anthropology Michelle C. LANGLEY Australian Research Centre for Human Evolution Environmental Futures Research Institute Griffith University, Brisbane, AUSTRALIA Email: [email protected] Thomas SUDDENDORF Centre for Psychology & Evolution Early Cognitive Development Centre School of Psychology University of Queensland, Brisbane, AUSTRALIA Email: [email protected] Abstract Mobile carrying devices — slings, bags, boxes, containers, etc. — are a ubiquitous tool form amongst recent human communities. So ingrained are they to our present lifeways that the fundamental relationship between mobile containers and foresight is easily overlooked, resulting in their significance in the study of human cognitive development being largely unrecognised. Exactly when this game-changing innovation appeared and became an essential component of the human toolkit is currently unknown. Taphonomic processes are obviously a significant factor in this situation, however, we argue that these devices have also not received the attention that they deserve from human evolution researchers. Here we discuss what the current archaeological evidence is for Pleistocene-aged mobile containers and outline the various lines of evidence that they provide for the origins and development of human cognitive and cultural behaviour. Keywords Foresight; Planning; Bags; Slings; Organic Material Culture; Long-Distance Transport This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/evan.21857 This article is protected by copyright. All rights reserved. Running Title: Containers in Human Cognitive Evolution Author Biographies Michelle C. Langley is a ARC DECRA Senior Research Fellow in the Australian Research Centre for Human Evolution at Griffith University, Brisbane, Australia. She specialises in traceological studies of osseous and shell technologies with her research revolving around the evolution of modern behavioural patterns. Thomas Suddendorf is Director of the Early Cognitive Development Centre and Professor of Psychology at the University of Queensland, Australia. He investigates the cognitive capacities of nonhuman animals and of young children, to answer fundamental questions about the nature and evolution of the human mind. 2 This article is protected by copyright. All rights reserved. 1. Introduction Foresight — the ability to think about future situations, what will happen or be needed — is an essential human adaptive strategy1 and consequently, the subject of intense interest in evolutionary human sciences. Throughout all this debate and discussion, the collection and carrying of items by an individual for future use is most frequently cited in connection to archaeologically identifying the origin and development of foresight.2-9 Rarely though, is it considered exactly how one would carry such items over (often significant) distances while going about one’s usual subsistence and social necessities. Obviously, people can only carry so much in their hands and be actively using them at any one time. Mobile ‘containers’ — objects for holding and/or transporting something — are devices presumed to have an extended antiquity, though no substantial research has yet been undertaken to specifically pinpoint when and how this technology developed amongst hominins. Instead, publications have been largely restricted to reporting ‘earliest’ instances (usually in the context of foresight development) or brief speculations regarding their origins.10-12 Given the importance of bags, baskets, pockets, slings, boxes, tubs, bins, sacks (etc., etc.) for human existence, this oversight by scientists appears incongruous. Here we unpack the importance of including a targeted investigation of the origins and development of mobile containers for advancing our understanding of foresight in hominins. We also outline the currently available evidence for mobile containers in the global Pleistocene archaeological record and highlight possible future research avenues to be explored. 3 This article is protected by copyright. All rights reserved. 2. The Importance of Foresight Increasingly, foresight is being recognised as a quintessential human adaptive strategy. The modern human capacity to prudently consider future events, to be driven to prepare, to make contingency plans, and embed distant events into larger narratives has recently become a topic of intense research interest in the behavioural sciences.13-14 A surge of research has explored the neurological bases of foresight,13 its late and multifaceted development,15 its role in clinical conditions,16 in social interaction,17 decision making,18 and in economics.19 The very capacity to innovate may be regarded as a sign of foresight. Indeed, it has been argued that what turns a problem-solution into an innovation is the recognition of future utility.20 Because we can recognise future use of solutions, we are motivated to retain, refine, and potentially share them, and this ability, in turn, is critical for the emergence of the cumulative culture that characterises the modern human condition. We know that actions which increase the likelihood of future survival and reproductive success are under intense selection pressure, resulting in most species being able to act in tune with significant long-term regularities such as day/night and seasonal changes. Through associative learning, animals can further adapt to local regularities and adjust behaviour so as to increase chances of rewards and to avoid negative outcomes. Humans have evolved even more flexible prospective capacities, enabling us to foresee not only what is likely to happen next, but to consider multiple versions of potential future situations, of motivations we do not currently experience, and even of remote events that we have never experienced personally.21 There continues to be debate surrounding precisely what makes human foresight unique,22-24 especially given that various behaviours other than foresight can lead to future benefits, such as associative learning, instincts, and chance. Experiments with non-human animals and young children have thus gone to great lengths to rule out such alternative interpretations.22 3. Foresight and Containers While stone tools have long dominated debates surrounding the development of foresight in hominins,25 mobile containers could be considered more direct evidence for this capacity as carrying 4 This article is protected by copyright. All rights reserved. a range of items — which one’s hands cannot contain alone — cannot only solve an immediate problem, but also multiple future problems, while simultaneously and dramatically facilitating subsequent innovation by enabling the accumulation and transport of raw materials and tools to one place or the keeping on your person. Mobile containers allow us to retain a local environment that keeps tools and resources handy wherever we go. They hence help us be prepared for the future. Mobile containers can be considered meta-tools, that is tools that serve as a tool for other tools,26 and their emergence may have been a catalyst for the growth of material culture. Of course, many animals use tools, cache food, build nests, and transport materials. Functional analogs of carrying devices are also relatively widespread. Marsupials have natural baby slings in the form of pouches to carry offspring, birds carry food in their beaks and throat sacks to feed their brood, and cercopithecines stuff their cheeks with food for later consumption. But do they make or use mobile containers with foresight like humans do? McGrew noted that containers are markedly absent even in ape material culture.27 Although apes transport food in hands, feet, or mouth and by tucking it into a groin “pocket”, they do not make containers to carry more items over longer distances. This is not to say that chimpanzee and other animals cannot use containers per se. Shumaker et al.’s comprehensive survey of animal tool-use lists various instances of container use, especially in the context of obtaining and consuming water,28 however, significant differences remain in humans in terms of the manufacture and sustained as well as versatile use of mobile containers. There are very few claims for manufacture of anything akin to a container among non-human animals. Rogers and Kaplan describe rehabilitated orangutans arranging half a dozen large oblong leaves in a fan shape to eat semi-solid foods away from a feeding station.29 Captive chimpanzees also sometimes shuffle leaves into a ‘plate’ to carry food.30 However, captive and rehabilitated animals may have learned this behaviour from humans, with great apes in particular known to copy human behaviour. In language-acquisition projects, for instance, bonobos have used human-made bowls, boxes, cups, and even backpacks to carry liquids, foods, and objects.31 There is no doubt animals can be trained to act in ways which resemble human foresightful behavior. In the wild, there is little to suggest that animals retain tools for remote future events, let alone that they invented tools to keep (more) tools. Tools may be