Periodic Reporting for period 1 - SKIN (Social Kinships and Cooperative Care: approaching relatedness in Later Prehistory through the analysis of women and children buried together)
Periodo di rendicontazione: 2023-02-01 al 2025-01-31
The project SKIN: Social Kinships and Cooperative Care investigates to what extent relatedness in later prehistoric societies was based on more than biological ties, and instead, included social concepts complementing and extending the nuclear family. Kinship is currently a burning issue of research across the humanities, social and life sciences, with implications for both the past and the present. In archaeology, it is critical to understanding major themes of past societies such as social organization, which includes the concept of family and the role of heredity as a determining factor for social inequalities. Anthropologists generally agree that kinship was central to social, economic and political structures in prehistoric societies, but often assume it is merely biologically constructed. However, ethnography has demonstrated that the human species is precisely the only one with an extensive cooperation among biologically unrelated individuals. One of the greatest advantages of broader social kinship is cooperative breeding and child rearing, which means that other members of the community provide essential support during the lengthy child development. This allows mothers to return to productive activities sooner and/or have new offspring. Non-maternal caregivers (allomothers) are extensively documented in contemporary small communities of similar size to prehistoric ones. Social concepts of kinship may extend to adoption, fostering and apprenticeships, which may give rise to close emotional bonds as well as cause people to share living spaces and work.
The SKIN project explores kinship and social relationships in prehistoric Iberia by analyzing multiple and double burials from the Copper and Bronze Ages (c. 3000-1000 BC). These types of graves provide crucial insights into past social structures, as individuals buried together likely shared a meaningful connection in life. Focusing on the exceptional burial site of Humanejos (Parla, Madrid, Spain)—which contains around 170 individuals, including a remarkably high number of non-adults—SKIN will examine how prehistoric communities defined kinship and caregiving beyond mere genetic ties. By integrating archaeological, bioarchaeological, and ethnographic approaches, the project will employ aDNA, Sr-isotope, and peptides analyses to investigate whether co-buried individuals were related by blood or if social constructs played a key role in their relationships. Special attention will be given to allomothering and cooperative care, two widespread but understudied practices in prehistory.
This research is particularly relevant to understanding the profound cultural and demographic transformations of the third and second millennia BC. While the Copper Age saw the rise of social hierarchy and inherited wealth—especially during the Bell Beaker period—the transition to the Bronze Age brought about an apparent return to egalitarianism, as seen in simpler graves with fewer signs of status differentiation.
The project is structured around four scientific research objectives:
1) analysing social kinship and allomothering patterns in a sample of ethnographic societies with
similar characteristics to prehistoric ones and developing a conceptual framework to interpret social relatedness in later prehistoric funerary contexts
2) determining the nature of the relationship between children and women buried together in the
study area through a) osteological analysis (morphological traits of biological relatedness and lifecourse events), b) aDNA (biological kinship) c) Strontium analysis (mobility and residence patterns) and d) peptide analysis (biological sex)
3) investigating i) if relatedness was more socially than biologically constructed in Copper and
Bronze Age societies of Iberia, ii) if those non-biological relationships between women and children can be explained as cooperative care or allomothering from different members of the group and iii) if these characteristics detected for the Iberian societies were similar to those of Central Europe
4) exploring the crucial role of social cooperation, beyond the purely biological links, for the survival of our species in past and present societies
The SKIN project explores kinship and social relationships in prehistoric Iberia by analyzing multiple and double burials from the Copper and Bronze Ages (c. 3000-1000 BC). These types of graves provide crucial insights into past social structures, as individuals buried together likely shared a meaningful connection in life. Focusing on the exceptional burial site of Humanejos (Parla, Madrid, Spain)—which contains around 170 individuals, including a remarkably high number of non-adults—SKIN will examine how prehistoric communities defined kinship and caregiving beyond mere genetic ties. By integrating archaeological, bioarchaeological, and ethnographic approaches, the project will employ aDNA, Sr-isotope, and peptides analyses to investigate whether co-buried individuals were related by blood or if social constructs played a key role in their relationships. Special attention will be given to allomothering and cooperative care, two widespread but understudied practices in prehistory.
This research is particularly relevant to understanding the profound cultural and demographic transformations of the third and second millennia BC. While the Copper Age saw the rise of social hierarchy and inherited wealth—especially during the Bell Beaker period—the transition to the Bronze Age brought about an apparent return to egalitarianism, as seen in simpler graves with fewer signs of status differentiation.
The project is structured around four scientific research objectives:
1) analysing social kinship and allomothering patterns in a sample of ethnographic societies with
similar characteristics to prehistoric ones and developing a conceptual framework to interpret social relatedness in later prehistoric funerary contexts
2) determining the nature of the relationship between children and women buried together in the
study area through a) osteological analysis (morphological traits of biological relatedness and lifecourse events), b) aDNA (biological kinship) c) Strontium analysis (mobility and residence patterns) and d) peptide analysis (biological sex)
3) investigating i) if relatedness was more socially than biologically constructed in Copper and
Bronze Age societies of Iberia, ii) if those non-biological relationships between women and children can be explained as cooperative care or allomothering from different members of the group and iii) if these characteristics detected for the Iberian societies were similar to those of Central Europe
4) exploring the crucial role of social cooperation, beyond the purely biological links, for the survival of our species in past and present societies
1) Ethnographic Analysis of Non-Genetic Kinship and Cooperative Childcare
A systematic review of the Human Relations Area Files (HRAF) provided extensive data on non-genetic kinship systems and cooperative childcare practices across different societies worldwide. This research resulted in a database covering information from over 20 societies, offering a valuable comparative framework for interpreting prehistoric social structures.
2) Ancient DNA Study at the Max Planck Institute
A total of 51 adult and non-adult individuals from Humanejos (Parla, Spain) were selected for ancient DNA (aDNA) analysis at the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany). Led by Wolfgang Haak and Vanessa Villalba Mouco, this study has already produced preliminary screening results, contributing to the reconstruction of biological and non-biological kinship patterns.
3) Peptide-Based Biological Sex Identification
Since aDNA preservation was insufficient for some individuals, peptide analysis was conducted on 30 non-adult individuals at the Medical University of Vienna. This proteomic approach allowed for the identification of biological sex in cases where genetic analysis was inconclusive, expanding the demographic dataset for kinship research.
4) Strontium Isotope Analysis for Mobility and Residence Patterns
To investigate mobility and social structure, strontium isotope analysis was performed on 44 individuals from Humanejos. These data are essential for understanding residence patterns and kinship organization, shedding light on population movement and the distinction between local and non-local individuals within the burial site.
A systematic review of the Human Relations Area Files (HRAF) provided extensive data on non-genetic kinship systems and cooperative childcare practices across different societies worldwide. This research resulted in a database covering information from over 20 societies, offering a valuable comparative framework for interpreting prehistoric social structures.
2) Ancient DNA Study at the Max Planck Institute
A total of 51 adult and non-adult individuals from Humanejos (Parla, Spain) were selected for ancient DNA (aDNA) analysis at the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany). Led by Wolfgang Haak and Vanessa Villalba Mouco, this study has already produced preliminary screening results, contributing to the reconstruction of biological and non-biological kinship patterns.
3) Peptide-Based Biological Sex Identification
Since aDNA preservation was insufficient for some individuals, peptide analysis was conducted on 30 non-adult individuals at the Medical University of Vienna. This proteomic approach allowed for the identification of biological sex in cases where genetic analysis was inconclusive, expanding the demographic dataset for kinship research.
4) Strontium Isotope Analysis for Mobility and Residence Patterns
To investigate mobility and social structure, strontium isotope analysis was performed on 44 individuals from Humanejos. These data are essential for understanding residence patterns and kinship organization, shedding light on population movement and the distinction between local and non-local individuals within the burial site.
This project has provided innovative insights into kinship structures and cooperative childcare in prehistoric Iberia (3rd-2nd millennia cal BC) by integrating ethnographic, bioarchaeological, and biomolecular approaches. The main contributions that go beyond the state of the art include:
1. New Perspectives on Kinship and Social Organization
By systematically analyzing non-genetic kinship and cooperative childcare practices in ethnographic contexts, this research has introduced a comparative framework for understanding prehistoric family structures. The creation of a database covering societies worldwide allows for broader cross-cultural interpretations of kinship systems beyond biological ties.
2. Largest Peptide-Based Sex Determination Study in Prehistoric Iberia
The project has conducted the most extensive study of biological sex identification for non-adult individuals from a single Chalcolithic site (3rd millennium BC) in Iberia. A total of 30 individuals from Humanejos were analyzed using peptide-based proteomics, providing unprecedented demographic insights into childhood and gender dynamics in prehistoric Iberia. This work, currently accepted for publication, is expected to have a major impact on bioarchaeological and prehistory research.
3. Groundbreaking aDNA Study on Co-Buried Individuals
While the final results are still pending, this project represents the first systematic aDNA study of all non-adult and adult individuals buried together in the same funerary structures for both the Chalcolithic and Bronze Age of the Iberian Peninsula. By focusing not only on biological kinship but also on non-biological social relationships, this research introduces an entirely new perspective on prehistoric burial practices and kinship networks. The implications of this study extend beyond Iberia, offering a novel methodological approach to analyzing co-burial patterns in prehistoric societies.
4. Reassessing Mobility and Residence Patterns in Prehistoric Iberia
The strontium isotope study conducted at Humanejos, now published, has challenged the previously assumed homogeneity of residence patterns in third and second-millennium BC Europe. While most studies to date describe a predominantly patrilocal system combined with female exogamy, our results suggest a more complex scenarioregarding residential patterns and kinship systems in pre-Beaker, Bell Beaker, and Bronze Age communities from Iberia. These findings highlight the need for a reassessment of traditional models of mobility and social organization in prehistoric Europe.
5. International Workshop on Non-Biological Kinship in Prehistory
In October 2024, this project hosted an international workshop in Vienna, bringing together over 20 experts in kinship studies from diverse disciplines, including social and cultural anthropology, archaeology, prehistory, evolutionary anthropology, and genetics. The workshop focused on non-biological kinship, methodologies for identifying it in the archaeological record, and future research directions for this emerging field in European prehistory. This event fostered interdisciplinary collaboration and laid the groundwork for future research initiatives, emphasizing the relevance of non-biological kinship in past societies.
1. New Perspectives on Kinship and Social Organization
By systematically analyzing non-genetic kinship and cooperative childcare practices in ethnographic contexts, this research has introduced a comparative framework for understanding prehistoric family structures. The creation of a database covering societies worldwide allows for broader cross-cultural interpretations of kinship systems beyond biological ties.
2. Largest Peptide-Based Sex Determination Study in Prehistoric Iberia
The project has conducted the most extensive study of biological sex identification for non-adult individuals from a single Chalcolithic site (3rd millennium BC) in Iberia. A total of 30 individuals from Humanejos were analyzed using peptide-based proteomics, providing unprecedented demographic insights into childhood and gender dynamics in prehistoric Iberia. This work, currently accepted for publication, is expected to have a major impact on bioarchaeological and prehistory research.
3. Groundbreaking aDNA Study on Co-Buried Individuals
While the final results are still pending, this project represents the first systematic aDNA study of all non-adult and adult individuals buried together in the same funerary structures for both the Chalcolithic and Bronze Age of the Iberian Peninsula. By focusing not only on biological kinship but also on non-biological social relationships, this research introduces an entirely new perspective on prehistoric burial practices and kinship networks. The implications of this study extend beyond Iberia, offering a novel methodological approach to analyzing co-burial patterns in prehistoric societies.
4. Reassessing Mobility and Residence Patterns in Prehistoric Iberia
The strontium isotope study conducted at Humanejos, now published, has challenged the previously assumed homogeneity of residence patterns in third and second-millennium BC Europe. While most studies to date describe a predominantly patrilocal system combined with female exogamy, our results suggest a more complex scenarioregarding residential patterns and kinship systems in pre-Beaker, Bell Beaker, and Bronze Age communities from Iberia. These findings highlight the need for a reassessment of traditional models of mobility and social organization in prehistoric Europe.
5. International Workshop on Non-Biological Kinship in Prehistory
In October 2024, this project hosted an international workshop in Vienna, bringing together over 20 experts in kinship studies from diverse disciplines, including social and cultural anthropology, archaeology, prehistory, evolutionary anthropology, and genetics. The workshop focused on non-biological kinship, methodologies for identifying it in the archaeological record, and future research directions for this emerging field in European prehistory. This event fostered interdisciplinary collaboration and laid the groundwork for future research initiatives, emphasizing the relevance of non-biological kinship in past societies.