Concepts from control theory date back to the early 1900s; however, the origination of control theory is usually ascribed to the publication of Norbert Wiener’s 1948 acclaimed work, Cybernetics: Control and Communication in the Animal and the Machine. To describe control theory simply, one could generalize that it is premised in understanding and describing self-regulating systems. In the decades following its conception, control theory and various elements of control theory were used to guide work in an array of diverse disciplines, including engineering, economics, mathematics, and medicine. It wasn’t until the early 1980s that Charles Carver and Michael Scheier presented control theory within the context of human behavior and psychology, and more specifically the regulation of health behavior through health psychology. Although introduced to human behavior in the 1980s, control theory has not been readily adopted in fields of health and exercise behavior. As described by Carver and Scheier, this could be in part because of the acceptance and prolific use of learning theories to understand human behavior, or potentially a hesitancy to consider a theory developed outside the realm of human or animal behavior. Regardless, the work of Carver and Sheier to apply control theory to human behavior and health psychology is the impetus that opens the door for application of control theory concepts in understanding exercise and physical activity behaviors. The purpose of this entry is twofold: first, to describe concepts of control theory as applied to health and specifically exercise and physical activity behaviors; and second, to discuss how these concepts have been and could be used in understanding and changing exercise and physical activity behaviors.
Although most terms used in this entry will be defined at the time of introduction, there are a few that should be more specifically discussed at this point. First, given the original work in control theory and subsequent application, it should be noted that control theory is also referred to as cybernetic theory or cybernetics in the literature. Clarification of the terms exercise and physical activity is also needed. While these terms are often used interchangeably, each is distinct. Physical activity refers to any movement of the body produced by skeletal muscle contraction that is associated with energy expenditure beyond a person’s basal level. Exercise, on the other hand, is considered a subcategory of physical activity and refers to any planned, structured, and repetitive physical activity carried out for the purpose of improving or maintaining at least one physical fitness component (cardiorespiratory endurance; muscular strength, endurance, and power; flexibility; balance; body composition; movement speed; or reaction time). For this entry the term exercise will be used, although principles of control theory are also pertinent to explaining and changing broader physical activity behavior as well.
The Negative Feedback Loop
The foundational concept of control theory lies in what is referred to as the negative feedback loop. The feedback loop contains several important features, beginning with an input function (a point where present conditions are evaluated by an individual), also called perception. Information gathered during perception is then compared against a reference value (also called the standard of comparison) by a comparator. This reference value represents a predetermined value of a condition, such as a predetermined behavioral or health goal. In this loop, the role of the comparator is similar to the concept of self-monitoring, where there is an assessment of current behaviors, any potential external influences, and progress toward an established standard (a goal). If a discrepancy is detected during this comparison between the assessment of present conditions and the reference value, a behavior is then performed (also called output function) to reduce the discrepancy by creating change in the present condition so as to have an impact on the environment (anything external to the person or system). This change in the environment then leads to a new perception by the individual and subsequent comparison against the established reference value. The feedback loop also includes what is referred to as disturbance, which is any change external to the individual or system (environment) that influences the feedback loop independently of the person’s own action, specifically entering the loop through environmental impact. This feedback loop is a closed circuit whereby the environment, person (system), and behavior all influence and are influenced by one another, similar to Albert Bandura’s construct of reciprocal determinism within the social cognitive theory. One important note to make here is that the purpose of the feedback loop is not to create a behavior, but rather to ensure that a predetermined, desired condition (as set by the reference value) is maintained through the comparison of the perception and reference value. Therefore, if a discrepancy is not detected, no change in behavior is needed.
An example of this feedback loop can be demonstrated by considering a person who is jogging in one’s neighborhood. Once on a jog throughout the neighborhood, most people primarily aim to remain in a safe portion of the road, clear of cars and other hazards. This maintenance is usually determined and addressed through visual monitoring of the road for traffic and by establishing ample room to jog safely between regular traffic and the curb or edge of the pavement. What would happen if a large moving truck approaches the jogger or if a shoulder that was once part of the road disappears? In using control theory with either of these scenarios, the jogger would detect a discrepancy between the perception of currently jogging in the road given these disturbances and the established safe jogging space reference value. For an avid jogger, this discrepancy would be quickly addressed by the jogger swiftly jumping off the street to continue jogging in a neighbor’s front lawn until the moving truck passed or the shoulder reappeared. As is apparent in this example, during any given jog numerous disturbances that require behavioral actions to eliminate associated discrepancies could occur.
Reference Point/Standard of Comparison
Given that the feedback loop heavily relies on a standard of comparison, it is important to understand the derivation and nature of the reference point. As conceptualized by Carver and Scheier, the reference point is dynamic and determined within the context of William T. Powers’s hierarchical system of goals. In this hierarchy, there are both higher order and lower order goals. Achievement of the lower order goals is intimately related with and essential for the achievement of the higher order goals. In this hierarchy, a higher order goal provides the reference values for feedback loops at the next lower order level. The highest order level within this hierarchical system is referred to as a system concept, as it represents both personal characteristics that one wants to embody as an idealized self-image and an attempt for one to minimize sensed discrepancies between how they currently are versus the ideal they desire to be. The second highest order level, principle control, specifies principles to use as reference in relation to the system concept; however, these are still qualities and are not specific to any one behavior. In the next lower order level in the hierarchy, referred to as program control, actions are identified although specific steps to accomplish these actions are not completely defined since specificity of some steps depends on situational circumstances. Subsequent lower order levels continue to monitor discrepancies between actuality and goals based on the next higher order feedback loop. Therefore, each level within the hierarchy has independent feedback loops that establish and adjust reference points for the feedback loop of the next lower order level, thereby demonstrating the dynamic nature of the goal system.
Again, the jogging example helps illustrate this hierarchical goal system. In this example, the individual is a 26-year-old female, Elizabeth, who views herself as a good friend and daughter, which represent the system concept. Given this view, Elizabeth usually attempts to behave in such a manner that her perception of her present-self matches this reference point, demonstrating self-regulation within this level. One example of how Elizabeth could accomplish this is to make certain that her mother feels special. This becomes the next lower order level reference point or goal, referred to as principle control since it is applicable to many behaviors, and thus could happen in many different ways. To self-regulate with such a broad reference point, program control feedback loops are then established at the next lower order level where the principle level goal is operationalized to specific behaviors.
In this example, Elizabeth can make her mother feel special by wearing her original wedding dress for her own wedding. However, she needs to be at a lower weight so that she can wear her mother’s dress, which can be accomplished by exercising daily (30–60 minutes/day). Although her behavior is generally defined at this point (exercising), it also includes a series of implicit if–then decisions based on the circumstances she encounters. Elizabeth’s normal 45-minute jog would keep her within the perimeter of her neighborhood; however, if a close friend called and needed to talk she might leave the neighborhood and jog over to her friend’s house. On a different day, it could be raining, and she might choose to go up to the school gym and ride a stationary bike instead of jogging. Each of these decisions is made to ensure that the goal of exercising 30 to 60 minutes daily is met, and each variation from the normal occurs to promote conformity to any of her other goals (e.g., not getting sick or ensuring she is a good friend). In each level of the goal hierarchy, the higher order feedback loop specifies the reference point for the next lower order level, whereby behavioral output is required for successful self-regulation in maintaining each reference point, and reference points are dynamic in that they reflect the feedback loop of the higher order goal.
Control Theory and Exercise Behavior
As previously mentioned, the application of control theory to exercise behavior is limited, although concepts found within control theory, especially those consistent with other behavioral and learning theories, such as social cognitive theory, self-regulation and the transtheroetical model, and processes of change, are consistently applied to and related with exercise. Some of the most prominent concepts congruent with control theory that have been applied to exercise are self monitoring, specific goal setting, goal review, the idea of tiered goals (goal staircase), and performance feedback provision. In fact, research supports self-regulatory strategies as both direct and indirect predictors of exercise behavior across the lifespan. Additionally, interventions that use self monitoring alone or with at least one other control theory concept (defined by some researchers as immediate goal setting, performance feedback, and review of behavioral goals) have demonstrated a significantly greater effect on physical activity behavior change than those that didn’t include any of these self-regulatory strategies.
In reading about how control theory concepts have been applied to exercise behavior, it is evident that these concepts fall into the broader theoretical context of self-regulation. Where self-regulation is defined as goal-directed behavior, exercising control over self in terms of maintaining or achieving a preferred standard, or feedback loops, it is only successful when it succeeds at both monitoring current conditions and behavior in relation to a goal (reference point) and making changes and adjustments as desired (based on a hierarchy of goals). In this context, control theory concepts are consistently supported as invaluable to understanding and initiating exercise behavior. However, given that research has heavily focused on predictors of initiating behavior, the roles of self-regulation and control theory concepts might differ when trying to understand and improve the maintenance of exercise behavior and habit formation.
In comparing control theory with many other prominent behavioral theories, two additional points need to be made. First, where many value expectancy and learning theories postulate that behavior change is influenced by self-reinforcement via reward for goal achievement and punishment when goals are not achieved, the control theory does not. Rather, as described earlier, control theory operates on the notion that humans inherently self-regulate through the goal-striving (reference point striving), discrepancy-reduction cycle. In this, reinforcement is only useful if it provides information (knowledge of results) that can help in the perception–goal comparison. Second, the concept of outcome expectations is also not directly addressed here. However, this idea is widely included throughout prominent theories and works in tandem with control theory.
While control theory has much overlap with other current and prominent health behavioral theories, control theories have been met with some criticism and misunderstanding. Some of this can be explained through the historical perspectives described earlier through the prominent application of learning theories and the hesitancy to consider a theory based on a machine model. However, a more macrolevel distinction between control theory and other current health behavior theories lies in the concept of reinforcement. Where many value-expectancy and learning theories postulate that behavior change is influenced by self-reinforcement via reward for goal achievement and punishment when goals are not achieved, the control theory does not. Rather, as described earlier, control theory operates on the notion that humans inherently self-regulate through the goal-striving (reference point striving), discrepancy-reduction feedback loops. In this, reinforcement is only useful if it provides information (knowledge of results) that can be integrated and used within a feedback loop.
Although prominent control theory concepts pertaining to exercise have been addressed within this entry, it should be noted that control theories include additional concepts and interested readers should see the References: list below.
- Carver, C. S., & Scheier, M. F. (1981). Attention and self-regulation: A control-theory approach to human behavior. New York: Springer-Verlag.
- Carver, C. S., & Scheier, M. F. (1982). Control theory: A useful conceptual framework for personality-social, clinical, and health psychology. Psychological Bulletin, 92(1), 111–135.
- Michie, S., Abraham, C., Whittington, C., McAteer, J., & Gupta, S. (2009). Effective techniques in healthy eating and physical activity interventions: A metaregression. Health Psychology, 28(6), 690–701.