stock market, since 1989. There are parallel surveys in Japan and China. Also, Karl Case, and now Anne Kinsella Thompson, and I have been doing surveys of US homebuyers and their perceptions of the market for single-family homes since 1993. The early surveys received support from the US National Science Foundation, with later surveys supported by the Whitebox Foundation and the Yale School of Management. The questionnaires for these surveys include open- ended questions with space that invites respondents to write a sentence or two. The questions are designed to stimulate respondents to think about what is motivating them, so that their responses can be analyzed in perpetuity. Since I started these survey projects, I have seen other survey organizations pursue sometimes similar objectives, and then stop. New survey tools like SurveyMonkey and Qualtrics are encouraging a proliferation of surveys but not a consistent strategy that is pursued over long periods of time. As of this writing, there does not appear to be much support for the routine collection of historical data in a form that will allow, decades hence, a truly comprehensive study of the dynamics of economic narratives. Tracking and Quantifying Narratives Research today needs improvement in terms of tracking and quantifying narratives. Researchers have trouble dealing with a set of often-conflicting narratives with gradations and overlaps. Even the simplest epidemic model shows that no narrative reaches everyone. In addition, the spread of a particular narrative may be largely random. The meanings of words depend on context and change through time. A story’s real meaning, which accounts for its virality, may also change through time and is hard to track in the long run. There is also the perpetual challenge of distinguishing between causation and correlation. How do we distinguish between narratives that are associated with economic behavior just because they are reporting on the behavior, and narratives that create changes in economic behavior?22 Economic researchers have to grapple with the same issues that have troubled literary theorists who try to list the basic stories in all of literature, who attempt to distill what defines these stories and makes them contagious (see chapter 2). At any time in history there are many contagious stories, and it is hard to sort through them. Literary scholars run the risk of focusing on details of the stories that are common just because the events are familiar in everyday life. They also face the difficulty of accounting for changes through time in the list of stories. Fortunately, research in semantic information and semiotics is advancing. For example, machine translation allows a computer to select the meaning of a word by looking at context, at adjacent words. The user asks, “What is the longest river in South Africa?” and Siri provides a direct verbal answer (“The longest river in South Africa is the Orange River”). Such search is now becoming well established around the world. However, semantic search may take a long time to reach the human mind’s abilities to understand narratives. In the meantime, researchers can still quantify the study of narratives by using multiple research assistants who receive explicit instructions to read narratives and to classify and quantify them according to their essential emotional driving force. Advances in psychology, neuroscience, and artificial intelligence will also improve our sense of structure in narrative economics. Companies like alexability. com (Alexandria), alpha-sense. com, prattle.co, and quid. com are beginning to offer intelligent searches of public documents and the media that could help organize information about shared narratives. As research methods advance, and as more social media data accumulate, textual analysis will become a stronger force in economics. It may allow us to move beyond 1930s-style models of income-consumption feedback and Keynesian multipliers that are still influential today and get closer to all the kinds of feedback that drive economic events. It will also help us better understand the deliberate manipulations and deceptions we have experienced, and it will help us formulate economic policies that take narratives into account. We should be looking forward to better understanding the patterns of human thinking about the forces that cause economies to boom at times and to stagnate at others, to go through creative times and backward times, to go through phases of compassion and phases of conspicuous consumption and self-promotion, to experience periods of rapid progress and periods of regression. I hope this book confirms the possibility of real progress in getting closer to the human reality behind major economic events without sacrificing our commitment to sound scholarship and systematic analysis. Appendix: Applying Epidemic Models to Economic Narratives Epidemiology, a subfield of medicine, developed most productively in the twentieth century. Its greatest contribution, a mathematical theory of disease epidemics, sheds powerful light on idea epidemics as they influence economic events. We can adapt this theory to model the spread of economic narratives.