Papers

Principal Investigator: Joseph Henrich

Our research program aims to construct a vertically integrated approach to culture and cultural evolution that synthesizes theory and methods from across the sciences, particularly from psychology, economics, biology, and anthropology. Below, we first broadly sketch the theoretical framework that links the various avenues of our work, then highlight certain key aspects of our research program, and finally review past work in setting out our current directions.

Cognitive foundations of culture: The theoretical core of our approach involves understanding the micro-level cognitive processes that influence human learning, and in particular those that affect social learning. To generate hypotheses about how these cognitive processes work, we consider how natural selection may have shaped human learning to allow individuals to most adaptively acquire ideas, beliefs, values, and practices from other individuals. To structure this theorizing, we construct formal evolutionary models that allow us to better assess the logic of particular hypotheses and to generate more precise predictions. Hypotheses about how we learn from others have been tested using a wide range of data from diverse fields, including both laboratory and field studies.

Cultural evolution: Building up from these cognitive and evolutionary foundations involves taking what is known about human social learning, usually grounded in evolutionary hypotheses, and formalizing this in cultural evolutionary models. Such mathematical models show how individual cognitive processes, through social interaction, can give rise to emergent sociological phenomena. This approach permits the development of theories about higher-level phenomena, such as institutions, ethnic groups, and social classes "from the ground up" by linking genetic evolution to cognition to cultural evolution. By making clear predictions about population-level patterns and phenomena, ideas about cognitive and social interaction can then be applied to empirical patterns from anthropology, history, sociology, and economics.

Culture, cognition, and decision-making: The third rung in this theoretical scaffolding focuses on how the products of cultural evolution influence behavior and psychology. By giving rise to partially integrated sets of beliefs, values, and institutions, cultural evolution can potentially affect people's motivations, goals, and reasoning processes. Using a variety of experimental and ethnographic tools, often bringing the "laboratory to the field", we have sought to begin charting culture's effects.

Culture-gene coevolution: This final step alters how we think about human evolution. Because humans have likely relied on high-fidelity cultural learning for hundreds of thousand of years, cultural evolution may have influenced our species' genetic evolution in ways not relevant to less cultural species. The cultural transmission of the practice of cooking meat (and making fire), for example, appears to have influenced our digestive system in ways that explain its peculiarity vis-à-vis other mammalian omnivores. Of particular interest to us, however, is not the digestive tract but the possibility that cultural evolution may have constructed cooperative institutional forms that, by spreading and persisting over long periods, have shaped the selective environment faced by the genes that influence our species' social psychology. This line suggests that there may be elements of human social behavior (e.g., aspects of altruism) that cannot be understood without considering the interaction between culture and genes. As above, formal models test the logic of verbal arguments and generate precise predictions.

Principal Investigator: David Reich

Building an Ancient DNA Atlas of Humanity: Ancient DNA allows us to go beyond the two-dimensional understanding of human genetic variation based on the coordinates of latitude and longitude, and to develop a far more powerful three-dimensional understanding now adding the coordinate of time. We are working with archaeologists, local stakeholders, and others to study ancient peoples and cultures from all across the world to learn about humanity and answer questions about our shared past. 

Making ancient DNA accessible to archaeologists: At present, genome-wide ancient DNA analysis is so new and technically complicated that it can only be carried out by a small number of laboratories. But ultimately, ancient DNA analysis is likely to follow the path of radiocarbon dating, another scientific technique that transformed archaeology that similarly was just the province of experts when it was first invented. Radiocarbon dating only realized its full potential once archaeologists mastered the skills to interpret this data, and we are similarly committed to putting ancient DNA into the hands of archaeologists.

Leveraging ancient DNA to understand human adaptation: Ancient DNA has already been a runaway success in improving our understanding of population movements and mixtures. But so far there has been little progress in shedding light on how the forces of natural selection have shaped human traits over time, because what is required for this is the ability to track the frequencies of mutations over time which requires large sample sizes. We are generating the large datasets needed to make such studies possible.

Leveraging an understanding of population history to reduce suffering and disease: The more we learn about human populations, past and present, the more we can apply this knowledge to address practical needs such as targeting medical services to people who need it. A major focus of our lab has been to document how many endogamous groups in India have experienced population bottlenecks stronger than those in Ashkenazi Jews or Finns. This predicts that there will be many rare recessive diseases in India, which can be found and tested for using modern genetic methods. We are working alongside colleagues in India to carry out pilot studies to prove the power of this approach.

Principal Investigator: Terence Capellini

The goal of the research program in the Capellini Lab is to identify the DNA base-pairs that mediate human- and primate-specific biological traits and their relationships to disease. The primary focus of the lab is on the musculo-skeletal system with an emphasis on identifying key regulatory elements or enhancers for musculo-skeletal genes and finding variants, both in humans or non-human primates, which alter the functions of these enhancers to shape the skeleton. To accomplish this task, the lab uses a multi-disciplinary perspective including wet- and dry-lab assays to generate novel data-sets in the mouse and intersect them with datasets from human biology, genetics, and medicine. There are a number of other non-skeletal projects in the lab, including examining the functional effects of genetic variants introgressed from Neandertals into the modern human genome, and studies on the regulation of key genes involved in COVID-19 disease risk. 

Currently, the lab focuses on three main areas of research in musculoskeletal biology and disease: the genetics of joint development and osteoarthritis, the functional genetics of human height, and the genetics of pelvic girdle development and its relationship to human obstetrics and diseases of child birth. All topics are generally understudied areas in genetics and developmental biology, yet they are essential components of our unique human condition with associated diseases that impact hundreds of millions of people worldwide.

Principal Investigator: Erin E. Hecht

Research at the Evolutionary Neuroscience Lab asks how brains change in response to selection pressure on behavior, and how brains acquire heritable adaptations for complex, learned behaviors. 

One branch of the lab’s research compares brain-behavior relationships in humans and our primate relatives. Another line of work is focused domestic dogs and selectively-bred foxes, which are other highly encephalized, social species. 

Current areas of focus include:

• Neural and behavioral variation in domestic dog breeds and domesticated foxes
• Neural correlates of domestication and selection against aggression
• Neural plasticity during the acquisition of skills for which species have innate predispositions
• The relationship between individual variation in brain organization and predisposition to acquire new learned skills 

The lab’s methods include:

• Structural and functional neuroimaging in living humans and dogs
• Structural imaging in fixed brains of various canine and primate species
• Histology and digital microscopy
• Behavior testing and video analysis

Principal Investigator: Christopher W. Kuzawa

My group’s research explores developmental influences on adult biology and health, the psychobiology of human fatherhood, non-genetic forms of biological inheritance, and the energetics and evolution of the human brain. Our work also addresses the history and misuse of race concepts in anthropology and beyond.

Principal Investigator: Rachel Carmody

We study how the gut microbiome shapes human health and evolution

Life depends on success in acquiring energy and allocating it efficiently to growth, maintenance, reproduction and activity. Our lab studies the biological, behavioral, and environmental determinants of human energy gain and utilization, and how changes in these factors over evolutionary time have shaped the human body.

Our current research in the Nutritional & Microbial Ecology Lab probes the energetic consequences of physiological interactions between humans and the trillions of microbes resident in the human gastrointestinal tract. This microbial community promotes nutrient digestion, synthesizes vitamins, metabolizes xenobiotic compounds, and shapes host immunity, activities that can have profound energetic consequences for the human host. Critically, these microbial contributions to human energy gain are not fixed, but rather depend on diverse microbial niches linked to within- and between-person differences in diet, health, and genetic factors. Interrogating these human-microbial interactions promises new insight into the modulation of human energy gain in the past and present, a fundamental question of biology with implications for the approximately 1 in 3 people worldwide affected by energy surplus or shortage.

Principal Investigator: Martin Surbeck

Our research investigates the behavioral ecology of non-human primates, with a focus on our closest living relatives, bonobos and chimpanzees, in order to understand the evolution of human behavior. One branch of the lab’s research addresses questions related to causes and consequences of cooperation and competition within and between groups. For example, we would like to know what facilitates tolerance between groups; in what way social bonds and cooperative behavior link; how female bonobos came to occupy high dominance ranks within groups; and by what means mothers help their sons to reproduce. Another line of work is focused on documenting and describing the social and ecological differences between chimpanzees and bonobos in order to be able to better understand the selection pressures driving these striking differences.

Current areas of focus include:

• Ecological drivers of prolonged intergroup associations
• Behavioral and endocrinological mechanisms underlying intergroup tolerance
• The role of differentiated social relationships in within- and between-group cooperative exchange
• Mechanisms of within- and between-group cooperation in primates
• Evolution of behavioral diversity within bonobos and between bonobos and chimpanzees

Our approaches:

• We combine behavioural data collection in the field with non-invasively collected physiological markers to infer about behavioural mechanisms
• We investigate underlying evolutionary forces by studying the behavioural and ecological variation across groups, populations or species.

Principal Investigator: Daniel E. Lieberman

The Skeletal Biology and Biomechanics Lab’s mission is to study how and why the human body evolved to be the way it is —especially in terms of physical activity— and to use that evolutionary anthropological perspective to foster human health.   We are especially interested in how evolutionary approaches to studying the human body can help better prevent and treat mismatch diseases. These are conditions that are more common and severe because our bodies are imperfectly or inadequately adapted to novel environmental conditions. The biggest mismatch we study is lack of habitual physical activity, but we are also interested in:  

•  What kinds and doses of physical activities —walking, running, carrying, and more— did we evolve to do?
• How and why do different types and levels of physical activity affect the body's growth, function and maintenance as we age?
• How does physical activity interact with diet and other factors (genetic and environmental) to affect physiology, health, and aging?
• How are industrial and post-industrial environments changing people's physical activities hence their anatomy, physiology, and health in Western and non-Western countries?

To address these issues, we integrate experimental biomechanics and physiology in both the laboratory and the field with analyses of the human fossil record.

Major current projects include: 

• research on the biomechanics and evolution of walking and running (from head stabilization to foot function)
• studying the effects of physical activity on metabolism, reproductive function, inflammation,  age-related muscle loss, and the cardiovascular and musculoskeletal systems
• studying the physical activity transition in Rwanda and other places.
• integrating research on physical activity with diet and other environmental factors.

Principal Investigator: Janet Song

The Genetic Basis of Human Evolution

How did humans evolve? The Song lab applies a genetics and genomics lens to understand how humans evolved. In particular, we study how human-specific sequence changes result in neural specializations that ultimately impact cognition, social behavior, and motor control. To address the following themes, we integrate a wide range of experimental and computational approaches from diverse fields, including evolutionary biology, molecular biology, neuroscience, developmental biology, anthropology, and computer science.

What genetic variants contribute to human-specific traits? There are millions of variants between humans and chimpanzees. We use comparative methods to identify which of these changes might be functional, screen candidates using high-throughput functional genomics approaches, and recreate individual changes in primate cells and in mouse models for further study.

How does human evolution affect human disease? Research by us and others suggests that genomic regions with signatures of selection in humans may be preferentially implicated in diseases that affect human-evolved traits like cognition and social behavior. We are interested in further exploring this connection and applying what we learn about human neural specializations to relevant diseases like autism spectrum disorder and schizophrenia.

Tool development to accelerate the study of human evolution. We have previously generated human-chimpanzee tetraploid stem cell lines as a genetic model where the genomes of both species are in the same cellular environment and different types of gene regulation can be disentangled. We are continuing to develop new ways to use this model to study human evolution. We are also developing approaches to facilitate in vivo genomic screens and training machine learning models to predict the effects of human-specific genetic variants.

Principal Investigator: Kevin Uno

The Uno Lab’s main research focus is on understanding the causes and consequences of major transitions in terrestrial ecosystems over the last ~25 million years. This includes the spread of grassland ecosystems and its effect on mammalian and early human diets and their evolutionary trajectories.  Potential causes for grassland expansion include a decrease in atmospheric CO2 levels, changing rainfall patterns, vegetation-fire feedbacks, and herbivory.  We can evaluate the role of these mechanisms in deep time using geochemical techniques we have learned or developed in the lab.