11 Part 1 / Philosophy of Science, Empiricism, and the Scientific Method Chapter 2 Elements of Scientific Theories: Concepts and Definitions n this chapter we will discuss the basic building blocks of a scientific theory: the concepts which represent the “real world” phenomena being explained by the theory. The scientific Imethod requires that the nature of these concepts be unambiguously communicated to others. This requirement mandates the creation of theoretical definitions. A theoretical definition explains what is meant by the concept. Concepts must also be objectively observed. This requires that we create operational definitions, which translate the verbal concepts into corresponding variables which can be measured. We will elaborate upon each of these topics in this chapter. In the next chapter, we’ll see how the defined concepts and their associated variables are related to each other to form complete theories. Concepts and Constructs The basic building blocks of theories are concepts. A concept is a verbal abstraction drawn from observation of a number of specific cases. The critical term here is “observed”, because it means that there is a direct link between the concept (the abstraction) and its referents (the reality). For in- stance, we can observe a number of particular instances where individuals receive varying amounts of money for the work they have done over a given period of time. From these particulars we distill an abstraction and label it “income”. Similarly, we observe individuals and find some of them short, some tall and more of them in between; from these observations we generate the concept “height”. Chapter 2: Elements of Scientific Theories: Concepts and Definitions 12 Part 1 / Philosophy of Science, Empiricism, and the Scientific Method A construct serves the same function as a concept, but it is more abstract. It is not characterized by a direct link between the abstraction and its observed manifestations. For instance, “source cred- ibility” is a construct which has been used in studying persuasion. This term can be used in the same way as a concept, but we should recognize that we cannot directly observe different levels of source credibility in individuals. However, we can observe the various parts which make up the construct individually, and then combine them to get some overall summary. Constructs are built from the logical combination of a number of more observable concepts. In the case of source credibility, we could define the construct as the combination of the concepts of expertise, objectivity, and status. Each of these concepts can be more directly observed in an individual. Of course, we might also consider some of these terms to be constructs themselves, and break them down into combinations of still more concrete concepts, as illustrated in Figure 2-1. What we see if we do this is a set of constructs at decreasing levels of abstraction. Only at the bottom of this hierarchy are directly observ- able concepts. From a practical point of view, it matters little whether we call the verbal building blocks concepts or constructs. It is more useful to consider every concept to be at some particular level of abstraction. This level is determined by the distance of the concept from the directly observable ideas at the bottom of the hierarchy. To simplify discussion, in the future we will use the term concepts to refer to either concepts or constructs, recognizing that any concept can really be a very abstract idea built from the combination of many less abstract (more concrete) concepts. Definitions A scientific concept really consists of three parts: a label, a theoretical definition, and an opera- tional definition. We’ll examine each of these elements separately. Concept Labels One of the requirements of a theory is that it be in a form which can be communicated to any interested person in an unambiguous fashion, so that it may be tested and evaluated by others. A great advantage of using concept labels is that they facilitate communication. It is vastly more con- Chapter 2: Elements of Scientific Theories: Concepts and Definitions 13 Part 1 / Philosophy of Science, Empiricism, and the Scientific Method venient and efficient to refer to people’s “income” than to refer to “the amount of money people receive in return for having made their labor or their knowledge available to another”. It is also very easy, at this level of abstraction, to link one concept to another. If we are asked what interests us most in the field of communication, we might answer that our research focuses on the effect of “environmental change” on “task-oriented communication” in organizations. But a label, particularly for abstract concepts like “task-oriented communication”, is usually not sufficient to communicate the full meaning of the concept unambiguously. We need additional explanation. Theoretical Definitions The theoretical definition specifies the verbal meaning which is attached to the concept label. We need this explanation because the scientific method requires that others understand our theory and be able to criticize and reproduce our observations. If we fail to specify the meaning repre- sented by a particular concept label, we leave room for misunderstanding. As we’ll see below, the more abstract the concept that we’re using, the worse this problem becomes. To illustrate this, suppose that you ask a group of people to write down on an index card their explanation of the concept of a person’s “age”. You’ll probably find that most of the definitions mention things like “how long someone has been alive”, “the amount of time which has passed since birth” and other similar statements. The amount of overlap among these definitions probably will be very high, indicating high shared meaning. Now suppose you repeat this procedure, but this time you ask people to define the term “me- dia use”. You’ll probably get very different results. You might find, for instance, that half of the definitions have a central theme of time (for instance, “the amount of time people spend with me- dia”) and that the other half might focus on purpose (for instance, “whether people use media for entertainment, information, escape, etc.”). The amount of overlap among these definitions is much lower than the overlap for “age”. Figure 2-2 illustrates the relationship between abstraction and meaning overlap. “Age” is a more concrete concept, so the concept label itself communicates the meaning of the concept almost as well as the definitions. Thus there is high overlap. “Media use” is more abstract, and can be constructed in many different ways from the combination of a large number of more concrete ideas. This produces many differences in the kinds of definitions which different individuals spontane- ously produce. We call self-defining concepts like “age” primitive terms. Primitive terms are adequately de- fined by their attached concept labels. These are the labels which appear at the bottom of the level of abstraction hierarchy. Probably only a small number of concepts that we are likely to use in commu- nication research have such high degree of shared meaning that they are primitive terms. And even then, the high degree of shared meaning might only exist within a particular group, but may not be shared with other groups. “Communication Apprehension” might be well understood by commu- nication researchers, but poorly understood by psychologists. Consequently, we always risk being on thin ice if we use primitive terms and assume that shared meanings exist. The conservative approach (and therefore the recommended one) is to explicitly specify the meaning associated with each concept, regardless of the extent to which we think the meaning is shared. We do this because the rules of science demand that we use concepts understood by the whole community of researchers. We must have high meaning overlap, particularly for abstract concepts which are not self-defining. To achieve this, we must construct a theoretical definition for each concept in our theory. The procedures for creating theoretical definitions are summarized in Exhibit 2-1, along with an example of the process. We’ve deliberately chosen a concept which is both abstract and not com- monly used in communication research to illustrate the value of theoretical definitions. Operational Definitions We now have a concept label whose meaning is explained by a theoretical definition. But the rules of science demand that this concept be capable of being unambiguously and objectively observed by anyone. This means that we must create another type of definition, called an operational defini- tion. An operational definition translates the verbal meaning provided by the theoretical definition Chapter 2: Elements of Scientific Theories: Concepts and Definitions 14 Part 1 / Philosophy of Science, Empiricism, and the Scientific Method into a prescription for measurement. Although they may be expressed verbally, operational defini- tions are fundamentally statements that describe measurement and mathematical operations. An operational definition adds three things to the theoretical definition.An operational defini- tion describes the unit of measurement (We’ll discuss measurement in much more detail in Chapter Chapter 2: Elements of Scientific Theories: Concepts and Definitions 15 Part 1 / Philosophy of Science, Empiricism, and the Scientific Method EXHIBIT 2-1 Procedure for Creating a Theoretical Definition 1. Select a summary label. the sum of money spent on advertising in media use efficiency media (per capita), subscriptions, and 2. List the labels of all the more concrete con- rentals of media cepts which are encompassed by the label. 6. Continue this process of breaking down more time spent with media abstract definitions into a series of concrete money spent on media definitions, until all terms in the final defini- 3. Combine these labels into a verbal statement tion are concrete, self-defining concepts which which defines the summary label.