# Complex Contagions and the Diffusion of Innovations: Evidence from a Small-N Study

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## Abstract

The recent literature on “complex contagions” challenges Granovetter’s classic hypothesis on the strength of weak ties and argues that, when the actors’ choice requires reinforcement from several sources, it is the structure of strong ties that really matters to sustain rapid and wide diffusion. The paper contributes to this debate by reporting on a small-N study that relies on a unique combination of ethnographic data, social network analysis, and computational models. In particular, we investigate two rural populations of Indian and Kenyan potters who have to decide whether to adopt new, objectively more efficient and economically more attractive, technical/stylistic options. Qualitative field data show that religious sub-communities within the Indian and Kenyan populations exhibit markedly different diffusion rates and speed over the last thirty years. To account for these differences, we first analyze empirically observed kinship networks and advice networks, and, then, we recreate the actual aggregate diffusion curves through a series of empirically calibrated agent-based simulations. Combining the two methods, we show that, while single exposure through heterophilious weak ties were sufficient to initiate the diffusion process, large bridges made of strong ties can in fact lead to faster or slower diffusion depending on the type of signals circulating in the network. We conclude that, even in presence of “complex contagions,” dense local ties cannot be regarded as a sufficient condition for faster diffusion.

## Keywords

Ceramic techniques Innovation diffusion Weak ties Strong ties Kinship networks Complex contagions Agent-based simulations## Notes

### Acknowledgements

In India, the support of the Rupayan Sansthan was invaluable. We are grateful to Kuldeep Kothari for resolving all the logistical problems as well as Meet Kaur Gulati, Anil Sharma, Ira Sisodia, and Lakshman Diwakar for their assistance in the field. In Kenya, we are grateful to Jacqueline Kawira for her assistance in the field. Last but not the least, we would also like to thank all the Indian and Kenyan potters for their availability and their unfailing kindness. Mohamed Cherkaoui, Ivan Ermakoff, Cyril Jayet, and Jörg Stolz read earlier versions of the manuscript and provided instructive written remarks. We also thank JAMT referees for their invaluable critical feedback. We are grateful to Peter Hamilton for his careful linguistic revision. Usual disclaimers apply.

### Authors’ Contributions

The article arises from a common theoretical and methodological effort. Authors were however differently involved in the specific tasks needed to reach the final product. In particular, [Freda Nkirote M'Mbogori] especially contributed to field investigations in Kenya; [Valentine Roux] especially contributed to research design and field investigations in India; [Simone Gabbriellini] especially contributed to qualitative data coding, modeling and simulation, and data analysis; [Gianluca Manzo] especially contributed to research and method design, analysis of the literature, modeling, data analysis, and article writing.

### Funding Information

This work was supported by the ANR (The French National Agency for Research) within the framework of the program CULT (Metamorphosis of societies—“Emergence and evolution of cultures and cultural phenomena”), project DIFFCERAM (Dynamics of spreading of ceramic techniques and style: actualist comparative data and agent-based modeling) (no. ANR-12-CULT-0001-01).

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