Category Archives: Research

Cultural Brain Hypothesis, Cultural Evolution & Human Social Networks at Stanford University, California

This week I visited Stanford University, California. Jamie Holland Jones invited me to present my research on human evolution, cultural evolution, and social networks at the Stanford Anthropology Colloquium Series. I presented three related projects:

The Cultural Brain Hypothesis (in prep; co-authored with Maciek Chudek and Joe Henrich), describes the evolution of large brains and parsimoniously explains several empirical relationships between brain size, group size, social learning, mating structures, culture, and the juvenile period. The model also describes the selection pressures that may have led humans into the realm of cumulative cultural evolution, further driving up the human brain size.

Sociality Influences Cultural Complexity (2014; co-authored with Ben Shulman, Vlad Vasilescu, and Joe Henrich) on the relationship between sociality and cultural complexity.

Cultural Dispositions, Social Networks, and the Dynamics of Social Influence: Implications for Public Opinion and Cultural Change (under review; co-authored with Mark Schaller) describes a mechanism through which realistic human social network structures can emerge and the implications of these mechanisms for cross-cultural differences in cultural transmission and innovation.

Human Behavior and Evolution Society Conference in Natal, Brazil

I attended the 26th Human Behavior and Evolution Society (HBES) Conference in Natal, Brazil. I gave a talk on the Cultural Brain Hypothesis and the Cumulative Cultural Brain Hypothesis.

The paper (in prep), co-authored with Maciek Chudek and Joe Henrich, describes an evolutionary model of the evolution of brains and parsimoniously explains several empirical relationships between brain size, group size, social learning, mating structures, culture, and the juvenile period. The model also describes the selection pressures that may have led humans into the realm of cumulative cultural evolution, further driving up the human brain size.

Cultural Brain Hypothesis and Cumulative Cultural Brain Hypothesis at St Andrews, Scotland

This week I visited the University of St Andrews, Scotland. Kevin Laland invited me to present my paper (in prep) on the Cultural Brain Hypothesis and the Cumulative Cultural Brain Hypothesis. The paper, co-authored with Maciek Chudek and Joe Henrich, describes an evolutionary model of the evolution of brains and parsimoniously explains several empirical relationships between brain size, group size, social learning, mating structures, culture, and the juvenile period. The model also describes the selection pressures that may have led humans into the realm of cumulative cultural evolution, further driving up the human brain size. I presented the research to Kevin’s lab and to Andy Whiten’s lab. I will also be presenting the paper early next month at the 26th Annual Meeting of Human Behavior and Evolution Society (HBES) in Natal, Brazil.

While at St Andrew’s, I met with Andy Whiten, Luke Rendell, Kate Cross, Ana Navarrete, Daniel Cownden, Daniel van der Post, Cara Evans, James Ounsley, Andrew Whalen, Lewis Dean, and Murillo Pagnotta, among others. Kevin is currently on sabbatical at the University of Cambridge.

Digital Humanities Conference in Lausanne, Switzerland

I attended the Digital Humanities 2014 conference in Lausanne, Switzerland. Ted Slingerland, Brenton Sullivan, and I presented “A Large Database Approach to Cultural History”. We presented the goals, approach, design, challenges, and progress of the Database of Religious History.

As Technical Director of the project, I focused on the technical aspects. You can read more about our efforts to publicize the database here and here.

Cultural Evolution and How Sociality Influences Cultural Complexity at University of Queensland, Australia

This week I visited my alma mater, The University of Queensland, Australia. Mark Nielsen and Thomas Suddendorf (both of whom I was lucky enough to take classes with as an undergraduate) invited me to present my paper on how “Sociality Influences Cultural Complexity” and my chapter on Cultural Evolution. The chapter, coauthored with Maciek Chudek and Joe Henrich, will be appearing in the new Handbook of Evolutionary Psychology. I presented the research to the Evolutionary Psychology group, which I took great pleasure in, being a member of the group as an undergraduate.

While at Queensland, I also caught up with my Honours supervisor, Penny Sanderson, and my former colleagues, Morgan Tear and Matt Thompson.

Society for Personality and Social Psychology (SPSP) Conference in Austin, Texas

I attended the 15th Annual Meeting of The Society for Personality and Social Psychology (SPSP) in Austin, Texas. I presented a model at the Dynamical Systems and Computational Modeling in Social Psychology preconference. The model uses two principles of human decision making to produce the three key properties of human social networks – high clustering (a friend of a friend is likely your friend), low characteristic path length (“6 degrees of separation”), and a positively skewed degree distribution (most people have a few friends, but a few people have many friends).

My collaborator and advisor, Mark Schaller, presented a related model at a symposium on “The Role of Interpersonal Processes in Group Phenomena and Cultural Development”. The model presented some preliminary research using the model I presented to better understand the dynamics of social influence within social networks.

Overconfidence at Hokkaido University, Sapporo, Japan

I spent the last week at Hokkaido University in Sapporo, Japan. I was invited to present my paper on how “Sociality Influences Cultural Complexity“. I also helped set up an experiment that Joe Henrich, Steve Heine, and I are running in collaboration with Tatsuya Kameda and Wataru Toyokawa. We previously collected data in Hong Kong in collaboration with Takeshi Hamamura.

Hokkaido University, Sapporo, Japan 

Muthukrishna, M., Shulman, B. W., Vasilescu, V., & Henrich, J. (2013). Sociality influences cultural complexity. Proceedings of the Royal Society B: Biological Sciences, 281(1774).

Sociality Influences Cultural Complexity

Proceedings of the Royal Society B: Biological Sciences published my paper with Ben W. Shulman, Vlad Vasilescu, and Joe Henrich showing that sociality influences cultural complexity. Across two experiments, we show that access to more people (1) increases cultural complexity, allowing for cumulative cultural evolution and (2) reduces the loss of cultural knowledge and skill. We found that students paid most attention to the most capable of their mentors, but also drew inspiration from the others, suggesting that the benefit of greater interconnectivity is twofold: you have access to the best people and information, but are also able to recombine knowledge from a greater variety of people.

Nature News, Kurzweil AI, CKNW, and GlobalTV were among the media outlets that featured the research. I explain the research to Philip Till at CKNW below.

Experiment1

Experiment 1 showing difference between access to models on cultural complexity.

Muthukrishna, M., Shulman, B. W., Vasilescu, V., & Henrich, J. (2013). Sociality influences cultural complexity. Proceedings of the Royal Society B: Biological Sciences, 281(1774). [Download]

Human Behavior and Evolution Society Conference in Miami, Florida

I attended the 25th Annual Meeting of Human Behavior and Evolution Society (HBES) in Miami, Florida. I gave a talk on two laboratory experiments I ran on cultural transmission (in press). The experiments tested the predictions of several evolutionary models showing the relationship between sociality (population size, interconnectedness, etc) and cultural complexity.

My results show that when people can observe and learn from a wider range of teachers, groups can better maintain technical skills and even increase the group’s average skill over successive laboratory generations. These results suggest that the secret of our species’ success may lie in the combination of our imitative abilities and our sociality, not in our individual smarts.

Technical Director of The Database of Religious History

I was recently appointed the Technical Director of the The Database of Religious History (DRH). The DRH is one of the flagship initiatives of the Cultural Evolution of Religion Research Consortium (CERC).  The DRH aims to bring together, in a standardized, systematic form, data on religious systems (and later more general historical variables) from across the world and throughout history, from the earliest archaeological records up to approximately 1500-1600 CE. By creating a quantitative database of social complexity, warfare, ritual, religion, and resources from across the globe and throughout history in a manner that will allow systematic statistical analysis, we hope to discover new patterns in world history, and test of novel hypotheses about the evolution of social complexity.

As Technical Director, I am responsible for the creation of the database system and general infrastructure.

Sante Fe Institute Workshop on Network Structure, Political Hierarchy and Economic Inequality

I was invited to a workshop on Network Structure, Political Hierarchy and Economic Inequality at the Sante Fe Institute. The workshop, organized by Sam Bowles and Paul Hooper, brought together leading contributors to the theoretical literature on social networks, anthropologists and other field researchers using network techniques to study the social structure of small-scale societies. I had the opportunity to discuss social network analysis and its application to the study of social structures and culture with several lead social network researchers, including Matt Jackson and Rajiv Sethi.

The project is part of the Santa Fe Institute’s Dynamics of Wealth Inequality Project.

Society for Personality and Social Psychology (SPSP) Conference in New Orleans, Louisiana

I attended the 14th Annual Meeting of The Society for Personality and Social Psychology (SPSP) in New Orleans, Louisiana. I presented a poster with results from two laboratory experiments I ran on cultural transmission. The experiments tested the predictions of several evolutionary models showing the relationship between sociality (population size, interconnectedness, etc) and cultural complexity.

My results show that when people can observe and learn from a wider range of teachers, groups can better maintain technical skills and even increase the group’s average skill over successive laboratory generations. These results suggest that the secret of our species’ success may lie in the combination of our imitative abilities and our sociality, not in our individual smarts.

Human Behavior and Evolution Society Conference in Albuquerque, New Mexico

I attended the 24th Annual Meeting of Human Behavior and Evolution Society (HBES) in Albuquerque, New Mexico. I presented a poster with further results from my model of the coevolution of brains and culture. The model is a plausible explanation for the expansion of the human brain size during the Pleistocene.

Society for Personality and Social Psychology (SPSP) Conference in San Diego, California

I attended the 13th Annual Meeting of The Society for Personality and Social Psychology (SPSP) in San Diego, California. I presented a poster at the Evolutionary Preconference with preliminary results from my model of the coevolution of brains and culture. The model is a plausible explanation for the expansion of the human brain size during the Pleistocene.