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Friday, May 08, 2009

Is Stress a mere matter of choice?

Muscular Tension: An Explanation from a Methodological Behaviorism


A truism in psychology is that the activity of the striated musculature is maintained or reinforced by its consequences, and represents operant behavior. Yet, the striated musculature is divided into two main types that are different physiologically and are activated separately and not necessarily simultaneously. The question is whether they are different psychologically. That is, are different types of the striated musculature activated by different motivational principles? It is argued that separate motivational principles are imputed for different muscular types because of the private nature of muscular activity that is resistant to precise observation, but disappear with the application of experimental instrumentalities that can render these private events and their governing contingencies universally accessible or ‘public’. It is concluded that striated muscular activity is uniformly and consistently operant in nature, and can be functionally analyzed through a methodological behaviorism.

Operant conditioning is based on the cumulative record of consistent correlations between the universally observed or ‘public’ form or topography of behavior and its consequences. Operant conditioning embodies methodological principles, wherein the lawfulness of behavior is derived from a data language that precisely maps to the universally agreed upon facts of behavior. As a form of methodological behaviorism, operant conditioning principles directly consider only publicly observable behavior. Grasping, walking, talking, etc. are operant behaviors because they are modulated or ‘reinforced’ by their outcomes. Because these behaviors uniformly engage a specific organelle of the body, namely the striated musculature, a common presumption is that operant conditioning primarily reflects the conditioning of these muscles. Of course, convulsions, startle reactions, etc. do involve the striated musculature and can be mediated by neurological rather than purely cognitive causes, but in general muscular activity is guided by its functionality as consciously perceived.

It is commonly assumed that if striated muscles are activated, they are publically observed, and hence may be subsumed entire under an operant analysis. Yet only a fraction of striated muscular activity is observable publicly or privately. That is, the musculature may be activated yet not result in publicly observable responses, and neither may it be consciously or privately perceived by the individual. Ironically, the private activity of the musculature has long been made public through resolving instrumentalities (e.g., SCR, EMG) but rarely if ever has an operant analysis been employed to explain this behavior. Rather, tension has generally been construed to be an artifact of autonomic arousal that is elicited due to psycho-social ‘demand’. This interpretation regards muscular tension as subsumed under different motivational principles that do not incorporate contingency, such as the reflexive or S-R responses entailed by a fight or flight response, stress reaction, etc. (Marmot & Wilkinson, 2006). In this case, inferred mediating processes take the place of observed correlations between behavior and environmental events.

However, this conclusion may remain uncontested not because the relationship between tension and its governing contingencies is disproven, or because the relevant data are unobtainable, but because of a common misinterpretation of the semantics of ‘demand’. The purpose of this article is to argue that the same data and data language used to establish the concept that tension is reflexive or is a respondent can be reinterpreted to unequivocally demonstrate that muscular tension is an instrumental or operant behavior.

The Striated Musculature

Although the activity of the striated musculature comprises the majority of behavior as we understand it, its psychophysiology is not widely known. Muscle fibers are categorized into "slow-twitch fibers" and "fast-twitch fibers" (Squire et al. 2003). Slow-twitch fibers (also called "Type 1 muscle fibers") activate and deactivate slowly, but when activated they are also very slow to fatigue. Fast-twitch fibers activate and deactivate rapidly and come in two types: "Type 2A muscle fibers" which fatigue at an intermediate rate, and "Type 2B muscle fibers" which fatigue rapidly. These three muscle fiber types (Types 1, 2A, and 2B) are contained in all muscles in varying amounts. Muscles that need to be activated much of the time (like postural muscles) have a greater number of Type 1 (slow) fibers. When a muscle begins to contract, primarily Type 1 fibers are activated first, followed by Type 2A, then 2B. Type 1 fibers are often monotonically activated because of psychosocial ‘demand’ that in general does not engage fast twitch fibers. For an individual, this activation is only indirectly observed when these fibers subsequently fatigue, causing exhaustion and pain.

Muscular activation also causes systemic changes in the autonomic nervous system. Sympathetic autonomic arousal is elicited through the sustained contraction of high threshold motor units (Type 2) of the striated musculature, as occurs during running or weight training (Saito et al. 1986). But arousal may also be mediated by the sustained contraction of small low threshold motor (Type 1) units of the striated musculature (Mcguigan,1991), and can be measured directly through EMG (electromyogram) or through indirect measures of autonomic arousal (e.g., skin conductance response or SCR; galvanic skin response or GSR) elicited by tension induced arousal. Physiologically the neural pathways that detail how muscular tension instigates autonomic arousal (Gellhorn, 1967, 1972, Jacobson, 1970, Malmo, 1975) have been well established. Through a bi-directional connection between the reticular arousal system and muscle efferents, a dramatic decrease or increase in muscle activity throughout the body can respectively stimulate decreases or increases in sympathetic arousal. This striated muscle position hypothesis (McGuigan, 1993) holds that the critical controlling event for autonomic arousal is covert neuro-muscular activity, and that rapid striated muscular activity can “mediate and thereby control what has been called autonomic, cardiovascular, and electroencephalographic conditioning.” The question yet unanswered is how Type 1 fibers are conditioned.

Contingency and Demand

The contraction of Type 1 fibers occurs prior to and in tandem with type 2 muscular activation, and is essential to voluntary behavior. Type 1 activation also occurs to prime an individual for action and as such is also dependent upon the anticipated results of that activity. It thus follows that Type 1 fibres are commonly activated due to response contingencies. However, if type 1 muscular contraction occurs without the subsequent activation of type 2 musculature, then involuntary or reflexive mechanisms are generally imputed as represented by the ‘stimulus’ of demand. But does this concept of demand denote a true mechanism or is it merely a misrepresentation of the semantics or meaning of demand?

As popularly conceived, tension is a byproduct of reflexive processes (e.g. flight or fight) that are elicited by a requirement for performance represented by ‘threat’ or ‘demand’. But the requirement for performance entails a conscious or non-conscious appraisal of the consequences dependent upon performance or non-performance. These represent future contingent outcomes. Thus demand must implicate contingency. Hence demand cannot represent a stimulus event that elicits behavior, but rather denotes a response contingency that leads to the emission of behavior.

This is easily demonstrated through the facts of behavior. Specifically, sustained levels of muscular tension are commonly produced under continuous alternative contingencies or choices. For example, continuous decision making between alternative contingencies (e.g. doing housework or minding a child, working or surfing the internet, staying on a diet or eating ice cream, keeping a dental appointment or staying at home) is associated with sustained or tonic levels of tension that is painful. Surnamed the ‘Cinderella Effect’ from the fairy tale character who as a harried servant girl was first to wake and last to sleep (Wursted et al. 1991, 1996; Hagg, 1991; Lundberg, 1999), the continuous activation of type 1 motor units or muscles (also called Cinderella fibers) because of this psycho-social ‘demand’ causes them to eventually fail, and thus recruit other groups of muscles more peripheral to the original group, resulting in pain and exhaustion. In addition, as the name Cinderella suggests, these slow twitch fibers are slow to deactivate, and will continue activated even during subsequent intervals of rest (Lundberg et al, 2002). The aversive result of this long term activation conforms with McEwen’s model of ‘allostatic load’ (1998), which predicts that tension and arousal will be maladaptive when there is an imbalance between activation and rest/recovery. Specifically, continuous low level or ‘slight’ tension results in overexposure to stress hormones, high blood pressure, and resulting mental and physical exhaustion.

In these examples, the demand reflected by alternative or conflicting contingencies or ‘choices’ does not represent a discrete stimulus entity or entities that bypass cognition but rather comprises a cognitive event that denotes changing perceptual relationships between behavior and outcomes or a means-end contingency or ‘expectancy’. These alternative choices describe responses that lead to primary gains at the cost of moment to moment opportunity losses. Thus the primary gain of minding a child or accessing the internet comes at the moment to moment opportunity loss of performing household chores or office work. But what is the purpose of concurrent muscular activation? The sustained activation of type 1 fibers as elicited by the perception of alternative contingencies serves no direct functional purpose, but it may serve an indirect one. Sustained tension is painful, and as a rule pain imposes a new action priority to escape pain and to avoid future pain (Eccleston & Crombez, 1999). That is, pain serves to initiate avoidance behavior. Thus the pain of tension may serve to motivate an individual to escape from ‘no win’ situations wherein any choice entails loss. But if tension is due to information about the consequences of behavior, namely the avoidance of the painful entailments of tension, how can this be demonstrated?

Resting Protocols

The argument for the operant nature of type 1 muscular activity is that if tension only occurs when decisions result in moment to moment or imminent feasible or avoidable (i.e., opportunity) losses, then tension will not occur if there is no possibility of avoidance of future events, or no opportunity loss. That is, the loss remains, but the opportunity to avoid it does not. Thus, if tension occurs because it signals behavior that leads to the subsequent avoidance of the events that elicit tension, then it logically follows that tension is therefore ‘reinforced’ by prospective avoidance, and is an operant behavior.

A well known procedure used to eliminate the ability to avoid loss while responding under multiple alternative contingencies is called an exclusion time out (Zirpoli, 2005). Common in educational environments, an exclusion time out describes a period of time when an individual is restrained from performing all actions which are otherwise rewarding in order to extinguish targeted behavior (e.g. temper tantrums). Thus a child under time out must sit and not participate with classmates, engage in learning tasks, read a book, etc. Although the child incurs and is aware of loss, the difference is that this loss is unavoidable or non feasible. A time out is also the defining characteristic of resting. To rest is to take a time out from the choices or demands of a working day in order to achieve a state of relaxation. However, it does not implicate to what degree choices are reduced, mainly that they are. Thus, although resting may figuratively represent an exclusion time out, it does not literally match the definition. To do that requires a radical reduction of choices that entail imminent (i.e., moment to moment) feasible or opportunity loss, and this is implicitly or explicitly entailed in meditative procedures. The research consensus is that meditative procedures, including resting protocols that also eliminate or defer this mode of choice all correlate with an attendant state of relaxation (Holmes, 1984, 1988). For meditation and resting, an individual may be aware of choices and the opportunity loss incurred by not acting upon them, but also knows that avoidance of these losses is not possible. This demonstrates that tension is indeed highly correlated with the prospective avoidance of future events, and is an operant.

However, although the dependent measure of relaxation is shared by meditative and resting states, the independent measures for these have been expanded beyond the mere attenuation of choice. Thus for meditation, relaxation may not be primarily attributed to the reduction of choice, but to the manipulation of attention. This manipulation involves focusing attention on a stimulus event (concentrative meditation, Benson’s ‘relaxation response’). But as with the semantics of demand, the semantics of focused attention is also ill defined, and must also entail the restriction of choice. In effect, the focusing of attention restricts choice by avoiding environmental stimuli or the perception of the functional consequences of those stimuli, which conforms with the definition of mindfulness as choice-less awareness (Germer et al. 2005). Because meditation must entail moment to moment choice-less awareness or mindfulness, it may be inferred that the primary dependent measure of meditation, namely muscular relaxation, is also primarily due to the mindful or choice-less awareness implicit in meditation. (It must be stressed however that although mindfulness incorporates relaxation as one of its entailments, the modification of rumination that is integral to mindfulness influences other emotional responses that have no relationship to muscular activity, such as depression, regret, etc. In other words, mindfulness is not primarily a relaxation strategy, although it incorporates elements that induce relaxation.)

To reinterpret meditative and resting protocols as a ‘time out’ or ‘choice-less awareness’ makes the independent measures for relaxation equivalent. Thus meditation is rest because their respective dependent and independent measures are the same. Because type 1 musculature is easily activated and is slow to deactivate, nearly all choice that entails moment to moment imminent feasible loss (i.e., conflicting choices) must be eliminated or deferred for a continuous period of time for the musculature to totally relax, and this is what meditative and resting protocols implicitly do, and for mindfulness procedures, it is what they explicitly do. Yet because muscular activation is not painful or harmful in itself unless it is sustained, it is the persistence and not the degree of muscular activation that is deleterious. Thus the continuous options involved in a distraction filled environment that entails minor yet persistent gains/losses are far more painful and harmful than the short term and generally intermittent choices that populate our ruminations or worries. It follows that although ruminative behavior causes tension through the cognitive representation of incommensurate choices, it generally does not populate a working day, and if it occurs we often have time to recover from our intermittent worries. However, distractive environments are common, often continuous and inescapable, and result in the persistent activation of the musculature. Moreover, in this high tech world, we consciously populate our environment with continuous distractive choices from email to the web, but continue to misattribute the resulting tension to the content rather than context of our choices. That is, by emphasizing what choices we make rather than how our choices are related to each other, the origin of muscular tension derives from the wrong cause and engenders the wrong ‘cure’. Thus choice becomes incidental to tension as the latter is attributed to the level of activity rather than the choices engendered by that activity. The remedy for this error entails ultimately a redefinition of the very concept of stress itself.

The Semantics of Stress

“If you wish to converse with me, define your terms” (Voltaire).

In his class, the psychologist F. J. McGuigan (1993) would induce relaxation in his students through the technique of progressive relaxation. He would then drop a book to demonstrate how the startle reflex and related tension and associated arousal is inhibited or impossible without the presence of muscular tonus, a finding originally made by Sherrington (1909) and explained neurologically by Gellhorn (1967,1972). This underscored the physiological fact that tension is primarily not an artifact of arousal, but its cause. If the independent measure of contingency is added to the equation, the theoretical principle follows that tension is the body’s specific response to alternative response contingencies or choices. Because it indirectly controls and is controlled by the prospect of the occurrence or non occurrence of future events or reinforcers, tension is an operant. However, although tension and accompanying sympathetic arousal may be characterized as stress, it cannot be formally defined as stress. This is because the latter’s terms are not precisely defined.

An operant definition of tension differs from the classic definition of stress as “the body’s nonspecific response to a demand placed on it” (Selye, 1980). Yet these two principles are incommensurate not because of their predictions but because of their semantics. That is, Selye’s principle is not a scientific hypothesis because its terms are not clearly defined. The theoretical incoherence of the concept of stress explains why stress is resistant to a methodological behaviorism. It simply contains no terms that may be grounded on the publicly agreed facts of behavior. Nonetheless, a methodological behaviorism can increase our knowledge of the observable behavioral event, namely muscular tension and associated arousal, which in the popular lexicon at least is defined as stress.

Ultimately, tension is initiated by the perception of means end contingencies or expectancies. Tension is in turn instrumental in altering affect (i.e. it produces pain), which in turn intrinsically denotes the response contingencies (i.e. avoidance behaviors) that will remove the tension that causes it. This latter position conforms to the principle in cognitive neuroscience that affect is not prior to cognition nor is automatically elicited without cognition, but must be integrated with cognition (Storbeck & Clore, 2007). This is particularly important in the analysis of stress, since the common metaphorical representation of stress implies that stress is a ‘reaction’ to demand events that bypass appraisal or contingency. However, whether tension and arousal are stress or represent a kind of stress is immaterial to the pragmatic implications of an operant analysis of tension. Specifically, if the metaphor of ‘choice’ replaces the metaphor of ‘demand’ as the primary descriptor of the etiology of tension, then simple contingencies of reinforcement may provide a much more precise and uniform description of the operational measures that will permit us to predict and control the daily tensions that beset us. Nonetheless, this argument is won not by the parsimony and precision of a learning based explanation, but through the power of procedure to effect behavioral change. That of course is the mandate and justification of a true science of behavior.


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