Historical and Comparative Research on Social Diffusion: Mechanisms, Methods, and Data

Abstract Historical and comparative social scientists are increasingly interested in explaining the spread of innovations—which social scientists commonly refer to as diffusion and, broadly conceived, can include the spread of new ideas, behaviors, technologies, and institutions. However, in spite of the profusion of studies, researchers do not always specify a diffusion model or its underlying causal mechanisms. Whereas many studies document spatial diffusion, not all specify a vector, model flows of influence and information, or show how people and places are connected (tied) to one another. In reviewing some of the most important work on the spread of religion, violent conflict, and social movements over the last few decades, it is clear to us that social network analysis has revolutionized the historical study of diffusion. Even so, many studies have yet to embrace concepts, methods, and measures from social network analysis. Nevertheless, we are convinced that the combination of historical perspectives on change and innovation, new methods of historical data collection and analysis, and growing sophistication in the application of network concepts and models is shedding light on a host of historical questions and contributing to our general understanding of diffusion.