Theory as Explanation and Understanding

First and foremost, theories are explanations—explanations that lead to, and are driven by, cumulative knowledge. Theories guide the questions we ask and the research we design. Theories answer the “why” and “how” behind what we find in data. Such explanations can be formal or informal, long or short, but they should be clear and explicit. Most often, they assume the form of a causal statement: X occurs because Y caused it, in conjunction with (or because of the absence of) Z.

Theories also provide understanding, which is somewhat different from explanation. We can posit a theory about the causal relationship between two variables without knowing the mechanism that underlies the relationships; a theory that includes mechanisms achieves a deeper level of understanding. In some fields of the social sciences it can be said that there are two primary types of theory: (a) theories of explanation of why and how something occurs—for example, cumulative advantage/disadvantage theories that explain why variability among older people partly reflects social inequalities, and how social processes generate those inequalities over time; and (b) theories of orientation that provide a worldview and even a set of explicit assumptions or propositions, which lead us to see and interpret aging phenomena in particular ways—for example, postmodern theory, feminist theory, critical gerontology, or the life-course perspective. Although the latter are often called “theories,” they are, from another perspective, more often broader “paradigms” than theories. However, the frame and propositions they provide are extremely useful in developing more specific theories. In any case, both types are represented in gerontology today.

“An attempt to explain,” perhaps also adding “for now,” is probably the simplest and most direct way to define theory. This expression has the advantage of reminding us that theories are provisional and embedded in a process that involves rejections, refinements, and reconsiderations over time as we are confronted with new knowledge and data, and with changing people in a changing world. Another useful phrase, “theorizing,” turns the noun into a verb that reflects the ongoing dynamic of building explanations. Advances in methods, and in the identification of problems to be studied, are dependent on the knowledge—theorizing—that preceded them, just as they in turn shape the resulting knowledge.

The principal value of theory, then, lies in building knowledge in a systematic and cumulative way, such that empirical efforts will lead to integration with what is already known and help us to see gaps or inconsistencies in existing knowledge or between new knowledge and old. The principal use of theory is to provide a set of lenses through which we can view aging phenomena and make and interpret observations.

Barefoot Empiricism, Empirical Generalizations, and Models

Theory should not be confused with other steps in the process of knowledge development or the terms that have been used to describe them. For example, what James Birren, one of the founders of the psychology of aging, described as barefoot empiricism (Birren, 1973, p. 11) is particularly problematic. This can be seen in papers presenting table after table of data with little interpretation as to why these results occurred or why they matter. Many articles like this can still be found in gerontology journals today, but it is unclear what lasting contribution they make beyond mere description.

What have been called empirical generalizations represent a conceptual step up from barefoot empiricism: statements that describe findings that have been repeatedly observed across multiple data sources. Empirical generalizations are usually anchored in extensive reviews of previous research on a given problem, and are often the grounds for explicit and even competing hypotheses. The research process involves collecting data through methods intended to reduce sources of bias, especially reliable and valid approaches to measurement and, in the social sciences in particular, sound sampling. In all scientific fields, the statistical handling of data is highly scrutinized by reviewers.

These steps, taken together—a thorough review of previous knowledge, an explicit statement of the research problem, a concern for unbiased collection of data, and state-of-the-art statistical analysis—can produce empirical generalizations about a research problem that look impressive. Nevertheless, too many journal articles still consist of empirical generalizations that are basically accounts of covariation across or between variables. This limits knowledge development to a description of observations and relationships at a certain point in time, with little interpretation concerning mechanisms of why and how they are related—in other words, no theorizing.

Models represent another process in knowledge development. A model is a way to depict a theory. It portrays the relationships among the complex variables suggested by a theory. It is a prototype of how empirical generalizations might be related to each other. The development of models and approaches to model fitting are recent contributions of 20th-century statistical and engineering applications of basic science. However, a model is not yet a theory.

Why Theory Is Important

In the history of science, theory has proven to be of great importance. In addition to explanation and understanding, there are pragmatic reasons for investing in efforts to develop theory.

First, in fostering explanation through specifying why and how empirically observed phenomena are related, theory contributes to the integration of knowledge over time. A good theory identifies the problem and its most important components (concepts) based on the separate findings and empirical generalizations from research. It also describes the linkages among the concepts in a causal sequence, based on previous knowledge. A good theory does this in a way that is clear, concise, and testable. This enables future investigators to test, refine, or refute it, thus advancing future knowledge development.

Prediction is another pragmatic contribution of theory. Theory-driven studies can point to new research directions based on findings that are partial, unexpected, or even anomalous and might otherwise remain hidden. Predictions based on theory can create radical shifts in the way we understand human life and the world around us. This is most obvious in the natural and biological sciences: Darwin’s theory of natural selection led to a revolution in human biology; Mendeleev’s theory led to the prediction of new elements in the periodic table; Einstein’s theory of relativity led to the discovery of new planets and eventually to the atomic bomb.

Theories also guide interventions to improve human conditions. Theory is valuable when we attempt to apply or advance existing knowledge in order to solve problems or alleviate undesirable human conditions. This can be seen in most organizations whose structures and actions are guided by popular theories about effective management, leadership, and communication. At a global level, the usefulness of theory in technological intervention is obvious in applications related to communication. In little over a century, communication has developed from the telegraph to Internet connections that can connect refugees in rural Somalia to reporters in London in a few seconds.

Other interventions are behavioral and social, though these have less often been informed by rational theories. At the macro-social level are the actions of governments, whose interventions through public policy are intended to ameliorate problems, such as subsidies meant to keep people above poverty in old age or supports meant to delay the institutionalization of older persons through the delivery of home health care and meals. These interventions can sometimes be evidence based, but they are rarely based on strong theory. At the micro-social level are interventions by practitioners who serve older people. These daily provide help and assistance to elders in need. Their efforts, which are routinely touted as being anchored in “best practice” models, most often reflect empirical generalizations concerning practices employed in the past.

The difficult task of implementing effective public policy and service delivery is exacerbated by the fact that little funding is available for the evaluation of these efforts. What is clear is that these interventions rarely rest on strong theory. If we do not understand the theory (the why and the how) of the problem, how can we best set up an intervention to fix it?

Goals and Emphases

Since the previous edition of this handbook, important developments have occurred within each of the disciplinary areas reflected in gerontology—the biology, psychology, and social sciences of aging, as well as in policy, intervention, and practice. A primary goal of this edition—with 35 chapters, 718 pages, and 70 contributors—is to update researchers, professionals, and students of aging on the latest theoretical developments across these traditional areas of gerontology.

A second goal is to foster “transdisciplinary” theories of aging by expanding concepts and explanatory systems across traditional boundaries. Critical advances have been made in transdisciplinary theories on circumscribed topics. Indeed, this is where much of the action in theory now resides and will continue to move.

A third goal is to increase attention to matters of variability and diversity in aging processes, from the cellular level of biological aging to the societal level of public policy. We asked chapter authors to consider the following issues: How sensitive are theories and concepts to matters of variability and diversity in aging—for example, to differences by gender, race and ethnicity, social class, or culture? How might theories and concepts be revised or tested with these matters in mind? In an effort to treat matters of globalization, we have also increased the coverage of international topics and the roster of international authors.

A fourth goal is to be a catalyst for developing future theories. To this end, we have asked contributors to contemplate common questions that bridge past, present, and future:

Organization

The body of this handbook is organized into seven sections, six of which have its own introduction by an editor or associate editor. The section introductions not only highlight the key contributions of the specific chapters therein, but also provide a global orientation to the theories in that area and an integrated story about the section as a whole.

The next chapter provides an overview of the volume and an examination of age and aging as our central theoretical constructs. Part I—“Standing on the Shoulders of Giants: Personal Perspectives on Theory Development in Aging”—is a new feature of this edition. This part contains chapters from four of the most senior gerontologists of our day from the fields of biology, psychology, social sciences, and the policy and practice of aging. The essays give readers an intimate backstage view into history of theory development in their respective fields. They share their personal experiences with the process and prospects of developing good theory: disappointments and victories, barriers and opportunities, and solutions and advice.

Parts II, III, and IV—on biological, psychological, and social science theories and concepts of aging—have been mainstays of this handbook since its initiation. Each discipline has an important set of theoretical traditions of its own. In this edition, we have built up the section on policy, intervention, and practice theories and concepts (Part V) to reflect commitments their field is making in theory-based, in addition to evidence-based, application.

Part VI highlights the surge in transdisciplinary theory development. Despite the challenges of bridging disciplines, and of working with different research paradigms and methods, researchers have made significant breakthroughs in explanations of aging phenomena that crossed and integrated disciplinary perspectives. This cross-pollination has been fostered by interdisciplinary graduate programs and training grants, as well as by funding agencies, which have placed a premium on interdisciplinary team science. It is exciting to see the emergence of theories and models that have as centerpieces concepts around which multiple scientific disciplines can collaborate.

Part VII, the conclusion, discusses some of the challenges of theory building in gerontology and advances an agenda for the development of theories in the future. As the field of gerontology and research on aging continue to rapidly expand, the need for a strong theory will only grow.