KARLA HOFF is a lead economist in the World Bank's Development Research Group and Visiting Professor of Economics and International Affairs at Columbia University. She co-directed the World Development Report 2015: Mind, Society, and Behavior, a synthesis of the applications of behavioral economics to development economics. She uses applied theory, analysis of observational data, and lab-in-the-field experiments to study social interactions that have large economic impacts, including corruption, civic investments in neighborhoods, prejudice, and domestic violence. In behavioral development economics, she draws on sociology and anthropology, as well as psychology, to demonstrate the impact of social constructs, such as caste and race and the culture of honor, on perception and behavior. Social constructs affect perceptions and behavior in ways that create differences between groups that are intrinsically the same and so sustain the belief that they are intrinsically different. She is an Associate Editor of the World Bank Economic Review and co-edited The Economics of Rural Organization and Poverty Traps. She was a National Merit Scholar, majored in French at Wellesley College, served in the Peace Corps in the Ivory Coast, and earned a PhD in economics at Princeton University.