The World Development Report 2015 is based on three main ideas: bounded rationality, which limit individuals’ ability to process information and lead them to rely on rules of thumb; social interdependence, which leads people to care about other people as well as the social norms of their communities; and culture, which provides mental models that influence what individuals pay attention to, perceive, and understand. The report has two main goals: To change the way we think about development problems by integrating knowledge that is now scattered across many disciplines, including behavioral economics, psychology, sociology, anthropology, neuroscience, and political science. To help development practitioners use the richer understanding of the human actor that emerges from the behavioral sciences in program diagnostics, design, implementation, and evaluation. The central argument of the Report is that policy design that takes into account psychological and cultural factors will achieve development goals faster. The webinars will provide a brief overview of the key themes contained in the forthcoming World Development Report 2015, "Mind and Culture". This webinar on Understanding Behavior Change in a Social World will introduce the main themes of how a better understanding of such concepts as limited bandwidth, social norms and preference models can enable development practitioners to be more effective in their work. The webinar will provide the key ideas that frame the Report and examples of how apply these concepts to development practice.