Crossing the Pleistocene Human Threshold [from ‘homeless’ to ‘home base’ caves]
Matt Pope on when, why, where early humans start using CAVES as living spaces
Matt Pope wrote:
Chapter 2 [excerpts]
Thresholds in behaviour, thresholds of visibility
Introduction: cave locales in human evolution
This [chapter] addresses some of the challenges in answering a relatively simple question: when did hominins start routinely occupying caves as living spaces? Cave locales, which for the purposes of this paper are taken to include large overhangs (rock-shelters), enclosed or unclosed fissures, sea caves as well as entrances to karstic systems, occupy an important position in Palaeolithic archaeology. Caves loom large in our record of the Middle and Late Pleistocene in terms of number of known sites, the good degree of preservation of behavioural and palaeoenvironmental evidence and the sheer density of archaeological finds within concentrated areas of space and sometimes spanning long temporal sequences. In contrast to open-air locales, cave systems have produced the vast majority of important hominin fossils for the Middle and Late Pleistocene. Cave records contain multiple proxies for the reconstruction of human behaviour at local and regional scales and provide archaeologists with their key cultural sequences, often accompanied by dating proxies.
A single cave site will often provide a wider range of evidence and a deeper timescale than the cumulative total of open-air locales within any given region. As a consequence, cave contexts form a proportionately greater focus for research time and resources than the surrounding landscape. We only have to imagine a Palaeolithic record lacking any cave-derived evidence to see their impact on our understanding of the early human past. The absence of cave records for some periods and within particular geographical regions therefore significantly skews our ability to bring the full range of hominin behaviour into focus.
Caves also occupy an important place in the history of our discipline and wider public perceptions of the deep human past, being intrinsically associated with concepts of ‘cavemen’ and the idea of the cave as the earliest human home. …
… This [chapter] makes the case that the obstacles in identifying when hominin groups started to actively seek out and occupy caves, stems more from our lack of suitable analytical frameworks than the paucity of data. This paper reinforces the importance of the subject by considering the degree to which occupation of caves as persistent places in landscapes could represent a key evolutionary marker in human behavioural evolution alongside the more familiar innovations of percussive technology, hunting, the use of fire and symbolic behaviour.
Caves, persistent places and home bases as examples of human niche construction
The presence of ‘home bases’ – locations, seasonal or permanent, where resources from the surrounding landscape and extractive locales are centralised and redistributed – represents a hierarchical node in a model of hominin settlement. Home bases are largely lacking among primates yet ubiquitous in the settlement networks of Pleistocene modern humans up to the present day. It is therefore important to establish where, on this trajectory from ‘homeless’ early hominins to the present, we first see the appearance of structured asymmetries in the behavioural record. These asymmetries might manifest themselves as differences between the extractive (primary butchery, stone acquisition and primary flaking, organic tool manufacture) and domestic (food sharing, tool maintenance, sleeping spaces) spheres. The latter we might comfortably term home bases and, where demonstrably involving the modification, provisioning of space over time, could be considered an example of human niche construction. Home bases, constructed in terms of utility and centrality to wider, complex patterns of landscape use represent a human niche which persists to the present day in rural and urban settlement systems.
Consequently, establishing in the regional archaeological record the first persistent and apparently targeted use of caves as home bases, as opposed to opportunistic sleeping sites, is important. It indicates at a regional scale that hominins were capable of organising themselves in space and time in a radically different way, either compared to earlier hominins or to any observed group of primates. Furthermore, we might hypothesise that hominin populations which utilised fixed, persistent places as part of their ecology will exhibit a suite of other behaviours not seen in populations which did not operate in this way.
While the evolutionary preconditions which might separate those hominins that used cave locations as home bases from those who did not might be small, this threshold, once crossed, would have had big advantages for those groups which expanded into, or created, this niche. In Table 2.1 the affordances offered by cave sites are listed alongside their wider advantages to cave-using groups. While the table includes environmental, technological and social/cognitive advantages, these should not be considered as separate from each other. For example, environmental affordances can scaffold cognition in the same way that material culture can form part of a wider human distributed mind.
Currently cave occupation sites appear earlier in northern and southern latitudes than on the equator, but in all three regions [identified in this book] sustained and continuous records of cave occupation is only unambiguous after 500ka, and therefore within the Middle Pleistocene. This threshold in the archaeological record is crossed towards the end of the Lower Palaeolithic and is coincident with, or within 100ka, of the earliest instances of the Middle Palaeolithic in each region.
Modelling threshold lag
… The record of percussive stone technology and animal processing now extends beyond the Pleistocene and into the late Tertiary… As a result this record spans transformations in the global landscape which go far beyond the normal scale of archaeological frameworks and methods. The combination of tectonic processes (uplift, folding and rift valley formation), hydrological changes (river valley incision, migration and phreatic karst system formation) and landscape denudation (scarp recession, graben formation and collapse, and slope processes) all have the capacity to create capture points. These sedimentary ‘traps’ are then filled with the records of hominin behaviour only to be subsequently released, when eroded, into the wider landscape. Every geological substrate and associated landform within a given region will give rise to a particular rhythm of capture and release, and the prevalence of each substrate within each region will characterise the overall rhythmic character of the region itself. Add to this the patterns of fission and fusion in hominin demography, and the limits on carrying capacity set by ecological and climatic factors, and there is scope for significant differences in lag between thresholds from one region to another.
In summary, identifying the interplay between these two thresholds will not be straightforward given that we might expect the following:
Many complex, advanced behavioural innovations will be preserved within caves once they are part of the hominin landscape (fire, social feeding, structures etc.)
The full integration of these behaviours as part of niche construction will be centred on cave contexts if they are present in a region
The need to accurately correlate these thresholds with changes in planetary climate, hominin morphology taxonomy and cranial capacity makes it imperative to focus on the potential lag between behavioural and visibility thresholds. …
Convergence in the Middle Pleistocene: characterising a late behavioural threshold
[We] can clearly see the appearance (around 1Ma) and then the subsequent expansion (around 0.5–0.3Ma) in the number of cave records. Interestingly, this increase in cave occupation sites is not evenly distributed by latitude. In the sample of African and European sites, cave records appear earliest in Southern Africa and a little later in Europe, depending on the status of possible doline sites … The increasing use of cave sites in the ‘Neanderthal’ record of Europe and the record of cave use by Anatomically Modern Humans (AMH) in South Africa contrasts with the late appearance of cave contexts in equatorial Africa. …
… The fact that the first florescence of cave occupation is occurring at mid-latitudes may be underpinned by geomorphological controls of visibility, but it is also easy to conceive how increased seasonality and the challenges presented by climate change at the extreme limits of human occupation in both hemispheres could be identically selecting for new behaviours involving cave use, home bases and new patterns of landscape use.
In some regions the impression is given of a trend towards a reduction in the number of large accumulations of stone tools … while open-air sites increasingly show parts of complex chaîne opératoires involving prepared-core technology, more curation, specialised composite hunting technology and cave sites with distinctive signatures of tool use, sharpening and discard as well as use of fire and intra-site structures. …
Discussion: converging worlds, persistent places and the hominin home
… The evidence presented here suggests the possibility of a deeper evolutionary relationship between hominin populations and their landscapes which provide the affordances of cave, shelters and overhangs. This relationship could be explored if visibility and taphonomic processes are factored into the study. An important consideration here is the degree to which landscapes which offered caves also offered other affordances to early hominin groups. Even before caves were routinely used, the landscape could have offered safe contexts for repeated activities not associated with food consumption, such as sleeping. Prior to the emergence of later, more complex landscape use behaviour, with the possibility of Asymmetrical Behavioural Records, such landscapes would have provided locales away from lowland game and predator concentrations, extensive plateaus, interfluves and escarpments. These were not only useful for moving through incised landscapes but also for providing extensive views and thereby contributing to successful foraging and scavenging activities. These landforms are fringed by ecotonal areas of groundwater discharge, either through springs or larger resurgent rivers. In fact there are many reasons why we might imagine these landscapes provide not only important affordances, which might explain an early presence of hominins within them, but also a low chance of discovering their record of hominin occupation associated at greater distances in time.
… [Unless] we envisage early Homo as simply a hominin of the plains, lakes and river edges, then we must begin to consider more clearly how areas with contrasting topography could have provided additional affordances. How much depends on the relationship between the behavioural and visibility thresholds in very dynamic and erosive landscapes and whether loss through erosion sufficiently explains the lack of occupation signatures from these landscapes and requires further systematic investigation.
By contrast the records of the Middle and Late Pleistocene show qualitative differences in human behaviour, many of which are independent of the visibility threshold. The density of material occurring within caves, the more widespread and sustained use of fire and evidence for secondary butchery and complex artefact resharpening can be read against the wider changes in landscape signatures and stone tool technology to suggest that a significant behavioural threshold was crossed at this time and that niche construction of a different nature was being undertaken. The possibility that this was not taking place across all latitudes at a similar rate is a compelling one. Inter- and intra-continental scale audits of the archaeological record will be necessary …
… The Middle Pleistocene, far from being a “muddle in the middle”, is one of genuine high contrast with the landscapes of the early hominin record. The spatial distribution of tool manufacture, feeding, sleeping and social interaction come together where conditions allow into a Convergent Behavioural Record lacking for earlier periods and allow for the development of more complex and resilient settlement models. …
… Changes in lithic technology, the appearance of unequivocal hunting weaponry and flexible approaches to meat acquisition and redistribution form key parts of [the] package. The persistence of Asymmetrical Behavioural Records in some spatial/temporal contexts in Africa and Europe may indicate that not all hominin populations crossed the threshold to Convergent Behavioural Records together or that a flexible repertoire of landscape habitation was available.
Conclusion: the hominin home as constructed niche
This [chapter] began by exploring the obstacles to tracking behavioural vectors in the Palaeolithic record, especially given the timescales involved and complex processes which contributed to its formation. [I have] proposed that, even if caves were routinely used at earlier stages than a potential visibility threshold, changes in the archaeological record of landscape use and technological innovation are compellingly coincident with the appearance of sustained cave occupation. Behavioural convergence of hominin technology, habitation and sociality offer the cultural equivalent of a Petri dish, incubating complexity while extending resilience to environmental change at season and glacial cycle scales.
Ultimately the use of caves is not the most important factor here, it is the exploitation of spatial areas offering security and utility, which can then be structured and provisioned for habitation. The creation of such spaces, however temporary, was probably a threshold pushed against throughout the evolutionary journey of Homo and precocious examples of habitation sites should be expected, but it is as part of a package of large brained, predatory and fire-using hominins with flexible and complex technology that we see it emerge fully formed in the relatively recent Middle Pleistocene past.
This behavioural threshold could be regarded, not just as an indicator, but a potential driver in the ‘modernisation’ of multiple hominin lineages, including Anatomically Modern Human and Neanderthal populations, during the past half million years.
The Source:
Matt Pope, ‘Thresholds in behaviour, thresholds of visibility [etc.]’, in Crossing the Human Threshold, edited by Matt Pope, John McNabb, Clive Gamble, Routledge 2018
Evolutions of social order from the earliest humans to the present day and future machine age.