Official website for the Center for Research in Experimental Economics and political Decision-making. Sandra E. Black holds the Audre and Bernard Rapoport Centennial Chair in Economics and Public Affairs and is a Professor of Economics. She received her B.A. from UC. Within evolutionary biology, signalling theory is a body of theoretical work examining communication between individuals, both within species and across species. Bipolar disorders have been characterized by powerful fluctuations of energy, mood, and thinking patterns. Mood episodes (manic or depressive) could be considered as.