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Gianluca MANZO – Complex contagions and the diffusion of innovations: evidence from a small-N case study
October 12, 12:00 pm - 1:15 pm
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The Sociology Seminar: Thursdays, from 12:00 to 1:15 pm
Time: 12:00 am – 1:15 pm
Date: 12th of october 2017
Place: Room 3105, ENSAE.
Gianluca MANZO (GEMASS, CNRS)
Discutante : Paola TUBARO (LRI, CNRS)
« Complex contagions and the diffusion of innovations: evidence from a small-N case study »
Abstract : Granovetter’s classic thesis on the strength of weak ties states that single exposure through long-range ties facilitates the circulation of “whatever is to be diffused”. Recent literature on “complex contagions” qualifies this statement and argues that, when the actors’ choice requires confirmation from multiple exposures, it is the structure of strong ties that really matters. The paper contributes to this debate 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 adopting new, objectively more efficient and economically more attractive, technical/stylistic options. Qualitative field data show that, despite common contextual factors, 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 advice and kinship 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 exposures through heterophilious weak ties were sufficient to initiate the diffusion process, larger bridges made of strong ties can in fact lead to faster or slower diffusion depending on actors’ initial beliefs. We conclude that, even in presence of “complex contagions”, dense local ties cannot be regarded as a sufficient condition for faster diffusion.
Marine HADDAD, Nicolas ROBETTE, Sander WAGNER (Laboratoire de sociologie quantitative – CREST)