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The physics of dissent and the effects of movement momentum


How do ‘people power’ movements succeed when modest proportions of the population participate? Here we propose that the effects of social movements increase as they gain momentum. We approximate a simple law drawn from physics: momentum equals mass times velocity (p = mv). We propose that the momentum of dissent is a product of participation (mass) and the number of protest events in a week (velocity). We test this simple physical proposition against panel data on the potential effects of movement momentum on irregular leader exit in African countries between 1990 and 2014, using a variety of estimation techniques. Our findings show that social movements potentially compensate for relatively modest popular support by concentrating their activities in time, thus increasing their disruptive capacity. Notably, these findings also provide a straightforward way for dissidents to easily quantify their coercive potential by assessing their participation rates and increased concentration of their activities over time.

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Fig. 1: The association between velocity and irregular leader exit at different values of mass.
Fig. 2: The association between velocity and irregular leader exit for log-transformed quantiles of mass.

Data availability

The STATA dataset that supports the findings of this study is publicly available from the Harvard Dataverse at

Code availability

The custom code that supports the findings of this study is publicly available from the Harvard Dataverse at


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We thank D. K. Cohen, J. di Salvatore, C. Dworschak, C. Hendrix, D. Johnson, Z. Marks, E. Perkoski, K. Sikkink, T. Svoronos, P. Vianello and the participants of a Research Colloquium at the Carr Center for Human Rights Policy for their input, as well as A. Tischner, M. Berger, P. Engler and the participants of the 2014 James Lawson Institute for conversations that helped to inspire this study. The authors received no specific funding for this work.

Author information




E.C. derived the idea, and collected and coded data on the dependent variable. M.B. produced the compiled dataset. M.B. and E.C. formulated the hypothesis, designed the research, performed the analyses, produced the tables and graphs, discussed the results, and provided input to the manuscript.

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Correspondence to Erica Chenoweth.

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Competing interests

The authors declare no competing interests. Correspondence and requests for materials should be addressed to E.C. or M.B.

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Peer review information: Primary Handling Editor: Aisha Bradshaw.

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Supplementary Information

Supplementary Figure 1, Supplementary Tables 1–17 and Supplementary Discussion.

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Chenoweth, E., Belgioioso, M. The physics of dissent and the effects of movement momentum. Nat Hum Behav 3, 1088–1095 (2019).

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