Hominin Habitats and Habitat Reconstruction
The paleobiological unit focuses on the reconstruction of human habitats from three million until 20,000 years ago. This period relates to the development of culture (see research unit 'Culture') and corresponds to the Late Pliocene and Pleistocene in terms of geology. The Pleistocene bears witness to the appearance and evolution of the genus Homo in Africa, the initial dispersal within and beyond Africa, the early spread across Eurasia, and many other regional migration events to follow. We describe the environments inhabited by humans, and characterize and explain the specific relationships that led humans to prefer or avoid particular habitats, thereby restricting their geographic distribution. Our task is to analyze vegetation, climate, faunal, and landscape parameters for resource availability and use these factors as a major aspect in the development of resource cultures that accompany the process of “becoming human” (in cooperation with research units 'Hominins' and 'Culture').
The genus Homo evolved in Sub-Saharan Africa. Despite having access to stone technology as well as changing dietary preferences, representatives of the genus Homo were restricted to this area for a period of hundreds of thousand of years. Early human environments are generally described by their main components, for instance climate, vegetation, fauna, biomes, landscape forms, and other relevant features of the landscapes. Such descriptions of the environment encompass all environmental factors within the spatio-temporal realm defined by the distribution of a biological or social hominin group of interest. Summaries of such parameters permit the characterization of hominin environments in a general sense in order to make them comparable. We apply the concept of “ecospace” in such characterizations. By comparing the ecospace of different regions of the world at different times or among diverse hominin taxa, we can describe the habitats available for human habitation. Therefore, our analyses begin with detailed descriptions of hominin habitats, including those environments which humans had not yet inhabited.
It is the specific ecology that relates human individuals, groups, and species with their habitats. In order to ensure survival, hominins will stay in habitats where they can supply themselves with all resources required. Therefore, a group relates to its environment primarily through resource availability. The resource space provides all of the basic requirements for a group, including food (plants and animals), water, shelter, combustibles, raw materials, and other material or immaterial items. Each group exploits the resources provided by their habitat guided by specific cultural capacities and according to their individual and/or social performances. Thus, the resource space of a group may differ through time as cultural performances or conditions in their environment change. The resource space may even vary for different groups coexisting at the same time in the same region. To understand and assess the implications of changing environmental conditions through geological time on the resource space of early humans and their changing culture, and thus on their potential to expand, we compile data on:
− Paleogeographic changes (e.g., sea level, mountain uplift, drainage systems and/or glaciation patterns)
− Climatic changes (e.g., temperature, precipitation, climatic seasonality)
− Vegetation dynamics (e.g., vegetation type, openness of vegetation, biomes)
− Ecological profiles of faunas (e.g., ecological composition, density, frequency, biome linkage).
We collect such data in ROAD. The data stem from literature research, supplemented by the results of our own studies, including fieldwork, work in museum collections, and in the laboratory.
Relating humans with their habitats is performed in two different ways:
1) By mapping human groups and features of their environments and dynamics (supported by research unit 'Integration')
Hominins and Hominin Reconstructions
In the paleoanthropological part of the project, we explore the biocultural differentiation in hominin evolution between three million and 20,000 years ago. In the course of this process, hominin species, especially of the genus Homo, acquired new modes of living and entered previously inaccessible environments. The process is characterized by physical, cognitive, and behavioral developments resulting from the broadening of ecological relations associated with a progressive release from habitat restrictions, and an increasingly generalist biological settings that allowed for wider ranges of distinct cultural modes of living. As a result, these developments enlarged the potential of human expansion and enabled hominins to explore and occupy new ecological niches and geographical areas.
At the onset of the research center, we focused on the study of physical parameters, but through time, we broadened the list of traits relevant to “becoming human.” Progress during the last years with regard to physical, cognitive, and behavioral developments made it clear that understanding the nature of “becoming human” as a process with interdependent cultural and biological factors requires the study of features of all of these spheres and the exploration of their interdependencies with each other and the social and material environment. A locomotor apparatus specialized for bipedal endurance running has its complement in generalized hands with possibilities for power as well as precision grip, which together allow for diverse object manipulations.
Changing energy budgets accompany increasing brain size. Neuron density and neural metabolism go hand in hand with digestive systems of a mainly less specialized masticatory apparatus. Altered gastrointestinal organs shift dietary composition and probably gut microbiomes as well. The decrease in sexual dimorphism is likely a sign of broader social tolerance. Extensions of the childhood phase in human life histories enable longer learning phases in engagement with increasingly complex social and material environments. Extensions of the post-reproductive phase combined with intensification of alloparental care provide the opportunity of reducing birth spacing, thus increasing birth rate and augmenting cultural transfer across not only one, but several, generations.
Human evolution went hand-in-hand with a markedly growing range of social activities. These activities gained importance in the amalgamation and transfer of knowledge and skills closely linked to increasing complexity in technological behavior. Active transfer of knowledge and skills relies on social tolerance and group cohesion, which in turn require additional effort in prosocial behavior and communication. Increasing cooperative activities facilitated specialization. The number of interacting conspecifics and the frequency as well as range of social interactions increased exponentially during human evolution. Parallel to and interdependent with social engagement, material engagement expanded in human evolution, resulting in engagements between individuals, their conspecifics, and material elements of the environment. The development of cumulative culture gave rise to an intensification in traditions and innovations. Associated cognitive developments relate to the fields of learning, perception, memory, planning, understanding of causalities, and execution of complex processes and relationships.
Following the identification of physical, cognitive, and behavioral parameters related to “becoming human,” we examine these traits separately and in relation to one another. This supports the identification, characterization, and evaluation of hominin ecological relations. Based on these, we can assess ecological specificity and the expansion potential of hominin populations. By identifying relevant physical, cognitive, and behavioral parameters and studying their interrelatedness, this research unit provides fundamental documentary and conceptual work, which serves as a basis for further analyses of ecological relations and potentials for expansion in cooperation with the other research units.
The research unit ‘Cultural Evolution’ represents the archaeological part of the research center. Here we explore the increasing role that culture played as hominins expanded their home range in Africa and Eurasia between three million and 20,000 years ago. This long span of time begins with the advent of stone artifacts and ends during the Last Glacial Maximum. Simply stated, we consider three factors as potential drivers of expansions into new regions: 1) the unfolding of material culture as represented in the archaeological record; 2) the broadening of the cultural niche; and, 3) increases in cultural capacities. In terms of material culture, we study the increases in cultural capacities and cultural performances during four main periods of human behavioral evolution spanning the Oldowan, Acheulean, Middle Paleolithic/Middle Stone Age and Upper Paleolithic periods.
As we investigate the spatial and chronological distribution of different cultural developments, signs of innovations which delivered an increased potential for niche and territorial expansion for early humans become visible. Advancements in the production of stone tools, the diversification of the tool kit, developments in the acquisition of different raw materials, the increased use of organic artifacts, the use and control of fire, the production of fitted clothing, and the ways that these behaviors contributed to improving the subsistence strategies of humans can all be seen as critical innovations. Moreover, the presence of artifacts with symbolic meaning, such as ornaments, figurative art, or musical instruments, are important indicators of behavioral modernity, a trend which arises at the end of the Middle Stone Age in Africa and during the transition from Middle to Upper Paleolithic in Eurasia.
We examine the links between key technological and symbolic innovations that occur in the context of the spread of modern humans out of Africa and across Eurasia. We assess artifact assemblages, for instance, based on richness and their place within an economic and settlement system. We do this by studying lithic reduction sequences, interpreting the function of lithic and organic assemblages, and by analyzing the choice and provisioning of raw materials. Artifact typology also plays a role as a cultural marker in the case of handaxes, Levallois technology, Howiesons Poort segments, or split-based bone points, as these artifacts help to assess cultural affiliations. Analyses of tool diversity and other indices calculated from lithic assemblages allow us to deduce land use and mobility patterns of hominin groups.
We record data on lithics and organic artifacts, as well as additional traits such as the use of pigments, the presence and nature of burials, personal ornaments, artworks, and similar archaeological data not only from existing publications, but also via the study of existing collections and within the context of our own excavations. Sites providing excellent conditions to study these different aspects are located, for example, in Africa, Arabia and the Levant, along the Mediterranean coast and the Danube Corridor, as well as in South and East Asia. These data allow us to interpret the archaeological assemblages in question and spatially analyze them and specific traits they contain using our integrative GIS approach.
In addition to specialized tasks related to the different levels of integration, as described in more detail below, the research unit ‘Integration’ implements and maintains a research network that brings domestic collaborators, foreign contributors, and co-workers together. We hold periodical meetings and workshops, organize international conferences, and upon completion of different project modules, present the results to a larger scientific audience.
This research unit is subdivided into three parts: Part 1 focuses on GIS, database development, and environmental modeling; Part 2 examines indicators, models, scenarios–cultural characterization of hominins in their environment; and Part 3 studies theoretical issues, heuristic comparisons, methodological structuring, development of hypotheses, and testing.
Part 1: GIS, Database, Environmental Modeling
Part 1 ‘Integration’aims to provide an integrative database structure for the project. This is realized through a Geographical Information System (GIS) used for spatiotemporal analysis of the data. Thus, data collected by the other research units, as well as that provided by cooperation partners, are consolidated and, after thorough quality control, made available for interdisciplinary research. Furthermore, we generate new information about the early expansions of humans by conducting sophisticated parameter connection using web-based information systems.
The studies are carried out on different spatial (survey maps, regional maps) and temporal scales with corresponding modeling (e.g., interpolation, geostatistics, object orientation). They include reconstructions of paleoenvironment (e.g., climate, vegetation, land/sea distribution), as well as cultural development (e.g., centrality, periphery) and the spatiotemporal changes in different epochs (e.g., habitats and their utilization, demographic trends, "paleotraffic geography"). Simultaneously, the studies encompass control and precision analysis of the localization of the sites. These studies support analyses of the causes of expansions, test basic hypotheses, and develop transformation models.
Such a project requires the long-term arrangement of the database system with standardized metadata for permanent data storage and flexible data management with simultaneous updates of datasets of spatial (sites) and itemized information (attached specifications). This includes:
− Data evaluation (e.g., collection by digitalization, data mining)
− Data management, administration and analysis
− Data presentation in the form of a web-based information system
− Controlled data exchange between project partners (metadata portal)
− Controlled external access with brief retrieval periods
− Presentation of the project results.
Part 2: Indicators, Models, Scenarios
The focus of Part 2 is the integration of various kinds of empirical data into a uniform modeling background. The model reflects culturally specific ways in which humans relate to their environments in order to ensure provisioning with required resources. The specific relationships direct land-use and resource patterns, as well as mobility behavior, as reflected in migration and dispersal patterns on a larger scale.
Agent-based modelling (ABM) provides an ideal modeling framework in this respect, particularly for two reasons. First, a diversity of factors can be integrated regardless of their disciplinary background, as long as their impact on the spatial behavior of humans and human groups can be principally quantified. Second, because ABM is a simulation-based approach, it allows us to develop a framework in which competing hypotheses can be tested for their explanatory performance. Furthermore, ABM is ideally suited for experimentation in prehistoric systems. This research unit develops case-specific models on a variety of chronological and spatial scales. Every model integrates datasets provided by other parts of the ROCEEH project.
Part 3: Theoretical Issues
The aim of Part 3 is twofold: First, we provide the theoretical-methodological framework of the project and monitor ongoing methodological reflections; second, as we ensure the validity of these transdisciplinary results over the long-term, we define basic concepts clearly in a process that incorporates all participating scientific disciplines. For example, previous discussions involved precisely defining terms such as: 1) Homo vs. human; 2) dispersal, expansion, migration, translocation; 3) different forms of expansions–ecospace, resource space, range; 4) supply systems; 5) development vs. evolution; and 6) nature vs. culture.
Our scientists examine transdisciplinary questions that cannot be accommodated by just one of the discipline-specific research units. These questions comprise aspects which are methodologically central to the project, such as tracing population expansions in the archaeological context, or examining factors believed to be central to the development and dispersal of modern human populations. Approaches to the study of the adaptive value of different technologies, the importance of tradition versus innovation in a society, the evolution of individual communicative abilities including language and social organization all need to be studied in a broader context. Additionally, approaches from other disciplines which are beyond the main scope of the project (e.g., from ethnography, economics, sociology, linguistics, genetics) can be reviewed and critically evaluated for their potential of tracing developments in the archaeological record. Thus, the integrative research unit generates additional hypotheses thorough heuristic comparisons that can be subsequently tested using the pool of data created by the other research units. The results of these studies are integrated into the modeling of early human expansions, their causes, and consequences.