Conceptualized and developed by Michael G. Moore, the TTD has its roots in adult and distance education (Moore, 1973, 1983, 2013). In his early studies as well as in later publications, Moore stated that in any educational setting, there are four variables present. These are:
Transactional Distance Is an Objectively Measurable Construct
Dialogue is measured by variables such as direct or indirect participation of the learner in asking questions, requesting clarification, or demanding explanation for the course content or how instruction is presented. Structure is measured by variables such as direct or indirect control of the instructor in providing guidance, offering advanced organizers, or elaborating and clarifying course content. For measuring these variables, Saba and Shearer (1994) used speech acts of thirty individual learners while they were communicating with an instructor. In this study, the data were collected in thirty separate instructional sessions for each learner. We demonstrated that while the basic dynamic pattern held true for all learners, the interplay between dialogue and structure was unique for each student. It is important to note that since the TTD is concerned with the individual learner, we did not aggregate the data from the subjects. The data from each learner were analyzed separately on an individual basis. To assess the effect of instructional treatments on learners, it is important to study individually the data collected from each learner. Otherwise, individual differences are confounded and the research study may show perplexing results. (For a discussion on trait-treatment interaction analysis, see Chapter 5.)
Other researchers have studied key constructs in the TTD as well (see the Appendix). However, not all of these research projects can be considered to be within the theoretical paradigm of transactional distance. A paradigm is a set of consistent and interrelated concepts that are validated through studies using an identical method of inquiry (Kuhn, 1970). Nonetheless, researchers interested in the TTD rarely, if ever, have replicated research studies. This lack of conceptual and methodological consistency has created confusion and misunderstanding regarding the nature of transactional distance and how to study it. An example is studies in which researchers have measured “perception” of or “satisfaction” with transactional distance instead of transactional distance itself. Another example is studies in which the average score of one group of students who were subjected to an instructional treatment was statistically compared to the average score of those who did not receive the same treatment. These comparative studies completely ignore individual differences among learners. The key concepts in the TTD and their native method of study, system dynamics, provide a comprehensive and unique paradigm to study the teaching and learning process as a dynamic whole with interrelated components. Studies that use other concepts and methods do not completely comport with the paradigm of the TTD.
Transactional Distance Is a Dynamic System Concept
Components of static educational systems have a constant behavior. In these systems, all learners receive the same lecture and study the same instructional materials during the same length of time, and presumably achieve the same predetermined objectives in the same location. This is regardless of individual differences among learners, their prior knowledge about the course content, and their need to have access to different learning opportunities. In dynamic systems, however, learners receive differential instruction depending on their individual profiles, and can exhibit emergent learning outcomes that go beyond the predetermined learning objectives. Dialogue, structure, autonomy, and, thereby, transactional distance are different for each individual learner at each moment in time and modulate interactively as the educational session progresses. These variables affect each other and are affected by each other during a program of study; thus, their value changes interdependently on an ongoing basis. To illustrate the point, the dynamic relationship between structure and dialogue is depicted in the following causal loop diagram.
A short explanation of some of the essential concepts of system dynamics is necessary to understand the diagram in Figure 1.2. In this illustration, the more structure there is in a system, the less dialogue; the more dialogue, the less structure. An instructor and a learner, in this example, optimize their stock (level) of transactional distance as they engage in dialogue (a flow or a rate), while the instructor sets the required flow of structure for that individual learner. Stocks (levels) in system dynamics are analogous to how much water there is in a swimming pool, and flows (rates) are similar to the amount of water per unit of time that is added to the pool and is drained from the pool. In more technical terms:
FIGURE 1.2 Dynamic relationship between structure and autonomy.
Rates define the present instantaneous flows between the levels of the system. They correspond to activities, while the levels measure the resulting state to which the system has been brought by the activity. The rates of flow are determined by the levels of the system according to rules defined by the decision functions. In turn, the rates determine the levels. The levels determining a particular flow rate will usually include the level from which the flow itself comes.
(Hadjis & Papageorgiou, 2011, p. 1334)
Thus, in Figure 1.2, dialogue and structure are conceived as flows and transactional distance is conceived as a stock. (For a more detailed explanation of stocks and flows, see www.systemdynamics.org/DL-IntroSysDyn/stock.htm.)
Relations among the components in a dynamic system are governed by two types of feedback loops: positive and negative. The feedback loop in Figure 1.2 is negative as it is indicated with the minus sign in the middle of the diagram. A negative loop means that there is an inverse relationship between two components: That is, the more the value of a component increases, the less of another component is available in a system. In the context of transactional distance, the instructor receives information about the tolerance that the learner has for dialogue, and the learner receives information about the structure that the instructor has imposed on the teaching-learning process. Thus, the instructor adjusts the flow of structure to respond to the learner’s need for dialogue, and the learner adjusts his/her expectation of dialogue to the necessary structure. This dynamic feedback loop determines the stock of transactional distance at each moment of instruction for each individual learner as the process of teaching and learning is in progress.
Figure 1.3 shows an example of a positive feedback loop in which it is indicated that the more resources available to an institution, the more can be spent on curriculum and organizational development efforts. In turn, a more developed organization performs better and attracts more resources to that organization for further development. The positive loop is highlighted with a plus sign in the middle of the diagram.
FIGURE 1.3 Example of a positive feedback loop.
Positive feedback loops, combined with negative feedback loops, provide control mechanisms in a system.
In Figure 1.4, more enrollments lead to increased student population in a positive feedback loop.
FIGURE 1.4 Example of positive feedback loop showing the effect of enrollments on the total student population.
As shown in Figure 1.5, the more students graduate, the less the student population (a negative feedback loop).
FIGURE 1.5 Example of negative feedback loop showing the effect of graduation on the total student population.
The control process includes a positive feedback loop that consists of enrollments and a negative feedback loop that involves graduation (Figure 1.6).
FIGURE 1.6 Example of a negative and a positive feedback loop as a control mechanism.
There is no inherent value in these loops. A positive loop is no better or worse than a negative one—they have different functions and they play specific roles in various circumstances. Positive loops tend to amplify changes in a system and often produce exponential growth, and negative loops tend to negate changes and move the system towards equilibrium (Hadjis & Papageorgiou, 2011). Most living systems are dynamic and complex, and consist of many positive and negative feedback loops that modify their behavior as time passes. Similarly, a learner’s interaction with instructors, peers, and administrators is dynamic and complex, and consists of many feedback loops that change in time.
Key constructs in the TTD indicate the dynamic learning process of each individual learner at each moment in time. Consequently, methods of study that collect data at one point in time, such as test scores at the end of an academic term, do not reflect the evolving nature of teaching and learning. Living systems change in time, and data that are collected at one instance could change in the next interval. Researchers who collect one set of data that reflect a snapshot of the state of the learner or the instructor at one moment in time ignore the temporal nature of autonomy, dialogue, and structure, and consequently transactional distance.
In short, system dynamics is the preferable method of study for constructs in the TTD as it ...