A scientific theory is a public pronouncement that indicates what a scientist believes to be true about his or her specific area of investigation. And the beauty of scientific theories is they help us to 【M1】______ organize our thinking about a broad arrange of observations and 【M2】______ events. Imagine how life might be like for a researcher who plugs 【M3】______ away at collecting data and cataloging fact after fact with organizing 【M4】______ this information around a set of concepts and propositions. Chances are that this person would eventually be swamped by seemingly unconnected facts, thus qualifying as a trivia expert who lacks 'big 【M5】______ picture.' So theories are of critical importance to developmental psychology, for each of them provides us with a 'lens' which we 【M6】______ might interpret any number of specific observations about developing individuals. What are the characteristics of a good theory? Ideally, it should be concise, or parsimonious, and thus be able to explain a broad 【M7】______ range of phenomena. A theory with few principles that accounts of a 【M8】______ large number of empirical observations is much more useful than a second theory that requires many more principles and assumptions to explain the same number of observations. In addition, good theories are falsifiable — that is, capable of making explicit predictions about future events so that the theory can be supported or disconfirmed. And, as implied by the falsifiability criterion, good theories do not limit themselves to which is already known. Instead, they are 【M9】______ heuristic — meaning that they build on existing knowledge by continuing to generate testable hypotheses that, if confirmed by future research, will lead to a much rich understanding of the 【M10】______ phenomena under investigation. 【M1】