Early in her career she recognized that negative symptoms and associated cognitive impairments had more debilitating effects than psychotic symptoms, like delusions and hallucinations. While psychotic symptoms represent an exaggeration of normal brain/mind functions, negative symptoms represent a loss of normal functions, for example, alogia the loss of the ability to think and speak fluently, affective blunting the loss of the ability to express emotions, avolition, loss of the ability to initiate goal-directed activity, and anhedonia, loss of the ability to experience emotions. The papers describing these concepts have become citation classics, as determined by the Science Citation Index produced by the Institute for Scientific Information.