Interdisciplinary PhD Project in Prehistory and Physics

Laboratories :

Laboratoire Méditerranéen de Préhistoire Europe Afrique, LAMPEA UMR 7269

Physique des Interactions Ioniques et Moléculaires, PIIM UMR 7345

Duration: 36 months

Start date: October 1, 2026

Description

Beyond the Horizon: Approaching the First Peopling of Australia through the Modeling of a Complex Socio-Ecological System

State of the Art and Research Problem

The peopling of Sahul—a continental shelf whose exposed landmasses during periods of low sea level now correspond to Australia, Tasmania, and New Guinea—represents the first migration of Homo sapiens into an insular environment. While the chronological framework of the crossing from Southeast Asia is becoming increasingly well defined, the technical, environmental, climatic, demographic, and social conditions remain largely conjectural. The earliest evidence of human occupation in Australia dates to approximately 65,000 ± 6,000 years ago at the Madjedbebe site in the Northern Territory [1,2]. Genetic data indicate that Aboriginal Australians and Papuans from New Guinea descend from a common ancestral population that likely migrated from Southeast Asia [3]. This migration appears to have occurred as a single major event, followed by rapid genetic divergence and relative isolation, with limited subsequent gene flow between groups [3,4]. A demographic-ecological modeling study suggests that the colonization of Sahul occurred rapidly, within 156 to 208 human generations [5].

The archaeological implications of this recent demonstration of open-sea crossings without direct visual contact with the destination coastlines are substantial:

- Paleoanthropology: Genetic evidence consistently places the ancestors of Aboriginal Australians within the first wave of the rapid dispersal of Homo sapiens out of Africa (~70–75,000 years ago) [3,4,6].

- Paleogeography and climatic variations: During glacial periods, sea-level drops of up to –120 m profoundly altered coastlines, distances to be traveled, and navigation conditions. Although the hypothesis of crossings during low sea-level stands is favored—since it reduces distances—it remains unproven. Conversely, the potential advantages of high sea levels for navigation (e.g., lagoonal environments, opportunities for coastal navigation) have not yet been tested.

- Demography: The colonization and long-term occupation of a territory require a minimum number of individuals and sufficient genetic and sexual diversity, which vary depending on social organization. Only one study for Australia is currently available, proposing a scenario involving at least 1,000 individuals arriving simultaneously or within a very short time span [7]. This scenario requires further testing.

- Anthropology of technology: Mastery of navigation in maritime zones affected by strong currents implies significant technical skills for designing and constructing watercraft capable of open-sea travel over several days, effective steering, and transporting multiple individuals along with necessary provisions. Although such organic-material vessels have left no archaeological traces, they imply technical expertise and forms of craft organization (learning processes, transmission, experimentation/innovation) not previously identified.

- Social context: The successful crossing of open-sea spaces by a sufficiently large and diverse population capable of establishing a lasting presence in Sahul implies a level of social organization more complex than what is inferred from conventional archaeological data. This complexity appears particularly early in this geographical region.

Achieving a refined and robust understanding of the first peopling of Australia is therefore crucial. To date, only one study proposes a modeling approach based on cellular automata [6]. Although structurally simple and computationally efficient, a major limitation of cellular automata in archaeology lies in their reduction of socio-environmental dynamics to homogeneous local rules, thereby limiting their ability to represent behavioral heterogeneity, intentionality, and multi-scalar decision-making processes characteristic of human societies. Furthermore, these models become computationally costly as spatial resolution, simulation duration, or rule complexity increases. This limitation is particularly significant in large-scale settlement simulations requiring numerous iterations for calibration or parameter exploration.

This doctoral research will develop an innovative modeling approach based on continuous dynamic models of the Lotka–Volterra type (MLV), which make it possible to overcome some limitations of cellular automata, notably by providing a more formal analytical framework and reduced computational cost [8]. MLV equations constitute a classical nonlinear model of predator–prey dynamics, often used as a reference framework for coupled interactions between populations [9,10]. However, it should be emphasized that, in physics, complex systems—although dynamically nonlinear and sometimes chaotic—are based on ontologically simple entities and relatively stable interaction laws. Complexity emerges from the multiplicity and coupling of interactions, rather than from variability in the rules themselves [11]. In contrast, in socio- environmental systems, interaction rules may be historically contingent, culturally mediated, and evolving, thereby shifting the very nature of the complexity under study. MLV models therefore do not resolve the epistemological limitations associated with representing complex human dynamics [12]. Nevertheless, their use will make it possible, from a complex systems science perspective, to test the limits of formalisms inspired by statistical physics in accounting for socio-environmental dynamics, and to identify both robust structural properties of the system and irreducibly cultural or historical dimensions [13].

Method

The construction of a database of archaeological and contextual variables—characterizing their intrinsic properties (quantitative/qualitative, continuous/discrete, etc.) and integrating them into the archaeological frameworks of the regional Upper Pleistocene—will enable the development of different scenarios for the peopling of the Sahul continent. These scenarios will be developed and tested using continuous dynamic models.

To complement this approach, the project will incorporate a second modeling scale based on agent-based modeling (ABM) [14]. An agent-based model explicitly represents autonomous individual entities (agents)— such as individuals, human groups, or watercraft—endowed with properties, behavioral rules, technical capabilities, and interaction rules localized in time and space.

Within this framework, the MLV model will be integrated into the ABM developed במהלך the thesis in order to formalize certain demographic and environmental dynamics at the system scale. This integration will enable articulation between an analytical representation of population–environment interactions and the bottom-up approach characteristic of ABM.

The strength of this approach lies in its ability to link emergent dynamics observed at the macroscopic scale with behavioral processes operating at individual or collective levels. More specifically, in the context of the peopling of Sahul, these simulations will allow testing of various scenarios concerning:

- the demographic composition of founding groups,

- maritime mobility strategies (including navigability properties and vessel size, as well as required energy and technical expertise),

- contingencies and conditions of sea crossings under high and low sea-level stands,

- as well as social organization (e.g., food storage) and environmental constraints (e.g., winds, ocean currents) associated with navigation routes.

Ultimately, this doctoral project will contribute to the development of a multi-scalar model applicable to diverse archaeological contexts, by integrating theoretical and computational formalization of complex socio-environmental processes.

Références

[1] Clarkson et al. 2017, Nature, 547, p. 306-310 ; [2] O’Connell et al. 2018, PNAS, 115 (34) p. 8482-8490 ; [3] Bergstrom et al. 2020, Science, 367, 6484 ; [4] Malaspinas et al. 2016, Nature, 538 (7624), p. 207–214 ; [5] Bradshaw et al. 2021, Nature Communications, 12 : 2440 ; [6] Fregel et al. 2015, PlosOne, 10-6) ; [7] Bradshaw et al. 2019, Nat Ecol Evol, 3, 7, p. 1057-1063 ; [8] Bertuglia & Vaio, 2005 Nonlinearity, Chaos, and Complexity: The Dynamics of Natural and Social Systems (Oxford) ; [9] Lotka 1925, Elements of Physical Biology, Williams & Wilkins Company; [10] Volterra 1926, Fluctuations in the abundance of a species considered mathematically, Nature, 118, p. 558-560 ; [11] Holovatch, Kenna and Thurner 2017 European J. of Phys 38 p. [12] Wilson A. 2008, J. R. Soc. Interface, 5 (25) p. 865-71 [13] Knuuttila & Loettgers 2017 The British Journal for the Philosophy of Science, 68, p. 1007–1036; [14] Romanowska et al. 2021, SFI Press, 442 p

Joint supervision of the thesis

Dr. Jean-Pierre Bracco, Full Professor, Aix-Marseille University, LAMPEA

Dr. Marco Minissale, CNRS Research Scientist, PIIM

Scientific team

Dr. Sadruddin Benkadda, CNRS Research Director, PIIM UMR 7345

Dr. Florent Détroit, Full Professor, Muséum national d’histoire naturelle, HNHP UMR 7194

Dr. Jean-Marc Layet, Professor Emeritus AMU, PIIM UMR 7345

Dr. Samuel Seuru, Postdoctoral researcher, LAMPEA UMR 7269

Working Conditions

Knowledge of French is not required

The PhD thesis may be written in English

Final selection will be based on interviews held on June 9–10, 2026

Selection Criteria

Applicants should demonstrate a strong interest in modeling approaches and research questions in Archaeology and the Humanities, as well as in interdisciplinary approaches involving environmental sciences, physics, and mathematics. Candidates should have skills in one or more of the following areas: Mathematics, Physics, Environmental sciences, Programming

Application Procedure

Interested candidates are invited to submit their application by email to the two PhD co-supervisors at the

following addresses:

jean-pierre.bracco@univ-amu.fr

marco.minissale@univ-amu.fr

Application deadline: May 11, 2026 at 17:00 (CET, Paris time).

Applicants must indicate “Interdoctoral Contract 355 352” in the subject line of the email and include the

following documents:

Cover letter

Curriculum Vitae (including list of publications, if applicable)

Contact details of two academic referees

Master’s degree transcripts