Review
The cognitive activation theory of stress

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Abstract

This paper presents a cognitive activation theory of stress (CATS), with a formal system of systematic definitions. The term ‘stress’ is used for four aspects of ‘stress’, stress stimuli, stress experience, the non-specific, general stress response, and experience of the stress response. These four meanings may be measured separately.

The stress response is a general alarm in a homeostatic system, producing general and unspecific neurophysiological activation from one level of arousal to more arousal. The stress response occurs whenever there is something missing, for instance a homeostatic imbalance, or a threat to homeostasis and life of the organism. Formally, the alarm occurs when there is a discrepancy between what should be and what is—between the value a variable should have (set value (SV)), and the real value (actual value (AV)) of the same variable. The stress response, therefore, is an essential and necessary physiological response. The unpleasantness of the alarm is no health threat. However, if sustained, the response may lead to illness and disease through established pathophysiological processes (‘allostatic load’).

The alarm elicits specific behaviors to cope with the situation. The level of alarm depends on expectancy of the outcome of stimuli and the specific responses available for coping. Psychological defense is defined as a distortion of stimulus expectancies. Response outcome expectancies are defined as positive, negative, or none, to the available responses. This offers formal definitions of coping, hopelessness, and helplessness that are easy to operationalize in man and in animals. It is an essential element of CATS that only when coping is defined as positive outcome expectancy does the concept predict relations to health and disease.

Introduction

Stress is an old term, in English used for pressure or distress at least from the 13th century, and related to sources of strain. The purpose of this paper is to present a cognitive activation theory of stress (CATS). Over the last 30 to 40 years a considerable empirical basis has been established for the role of cognitive factors for ‘stress’ in man and animals. Ignoring this results in many claims of relationships between ‘stress’, strain, and health and are simply not true. We believe that a more precise and formal set of definitions may reduce the bewildering use of terms, which may cover the same phenomena. Therefore, CATS offers definitions formulated in symbolic logic presented separately at the end of this paper.

This is ‘cognitive’ stress theory because CATS assumes that the stress response depends on acquired expectancies of the outcomes of stimuli and available responses. We regard these as acquired (learned) relations between stimuli, and between responses and stimuli. We will deal with these phenomena as information-handling systems of the brain, and will accept that all advanced brains have such properties. It is an activation theory since it is based on neurophysiological activation and arousal concepts. It is a stress theory since it aims at explaining the psychobiology of conditions where people use the term ‘stress’, and are worried about possible health consequences.

Section snippets

Historical background

Hans Selye is frequently claimed to be the father of the stress concept. However, in his pioneer 1936 paper (Selye, 1936), a brief note in Nature, the term ‘stress’ was not used. According to tradition, this was because the medical establishment (and the referees in Nature?) found the term too unspecific, and too much used as a nonscientific attribution concept by the lay public. In his original 1936 paper, Selye simply described general, non-specific adaptation and maladaptation phenomena in

Four aspects of ‘stress’

Stress is defined and operationalized by stimuli (‘stressors’), subjective reports of an experience (humans only), a general non-specific increase in arousal (activation, and the feedback to the brain from this response (Levine and Ursin, 1991) (Fig. 1

. The four main aspects of stress. The load (1, stressor, stress stimuli) is evaluated by the brain (2) and may result in a stress response (3, alarm) that is fed back (4) to the brain. The physiological stress response may lead to training or

Measurement of ‘stress’

The four aspects of stress offer four ways of measuring ‘stress’. Current methods may cover one of the meanings, sometimes more than one meaning. The load (stimulus or ‘stressors’) (aspect 1) may be easy to measure, and often impress as the most objective way of measurement. However, even if it is easy to quantify external factors, it is the social and emotional factors that may determine survival in extreme environments (Ursin et al., 1991).

The experience or feeling of stress (aspect 2) is

When does the alarm occur?

The stress response is a general, unspecific alarm response occuring whenever there is a discrepancy between what is expected or the ‘normal’ situation (set value) and what is happening in reality (actual value) (Table 1

. When does activation occur?

For all variables controlled by the brain, at any point in time:
‘Set value’ (SV): the value brain is ‘set’ on for that particular variable
‘Actual value’ (AV): the real value of that variable.
Statement 1a: (SVAV)⇒Activation
and
Statement 1b: (SV=AV)⇒No

Expectancy: what does the stimulus mean, what can I do about it?

All brains store the relations between stimuli, and between responses and stimuli. This stored (learned) information is referred to as expectancy (Table 2

. The expectancy concept

Stimulus expectancy: Statement 3
When the subject has learned that one stimulus (S1) predicts the occurrence of another event (S2) this is referred to as stimulus expectancy:
Statement 3: S1ES2=(S1⇒S2)
Statement 3 is to be read: The stimulus expectancy S1–S2 means that S1 implies S2.
In classical conditioning, S1 is the

Dimensions of expectancy

Expectancies are quantified by three dimensions: acquisition strength, perceived probability, and affective value (Table 3

. Dimensions of the expectancy concept

Acquisition strength
Acquisition strength is referred to as H (‘habit value’), which is assumed to have values between 0 (minimum) and 1 (maximum). Formally, the strength of S1⇒S2 is expressed by H (S1ES2) and has values between 0 and 1:
Statement 5a: H(S1ES2)∈(0,1).
Or, in more detail:
Statement 5b: ∀S1ES2H(S1ES2)∈(0,1){0}.
Statement 5b is to

The CATS coping concept: positive response outcome expectancy

Coping is the acquired expectancy that most or all responses lead to a positive result. This leads to a reduced arousal level (Table 4

. Coping defined as positive response outcome expectancy

Coping is a positive response outcome expectancy
(Approach learning: A(S2)→1):
Statement 11: H(R1ES2)→1, PP(R1ES2)→1, A(S2)→1
Statement 11 is to be read: The habit value of R1 leading to S2 is high, the perceived probability of R1 leading to S2 is high, and the affective value of S2 is high.
(Avoidance learning: A(

Helplessness

Helplessness is the acquired expectancy that there are no relationships between responses and reinforcement (Table 5

. Helplessness and hopelessness defined as response outcome expectancies

Helplessness exists when:
Statement 13: H(R1ES̄2)→1, PP(R1ES̄2)→0, A(S2)→−1,PP(R1ES̄2)∼PP(R̄1ES̄2)
Statement 13 is to be read: Helplessness exists when the perceived probability of avoiding an unpleasant stimulus approaches zero. (Detailed readout: see Statement 11)
Comment:
From Statement 1a the arousal level is

Hopelessness: negative response outcome expectancy

Hopelessness is the acquired expectancy that most or all responses lead to a negative result (Table 5).

Hopelessness is more directly opposite of coping than helplessness, since it is a negative response outcome expectancy. There is control, responses have effects, but they are all negative. The negative outcome is his or her fault since the individual has control. This introduces the element of guilt, which may make hopelessness a better model for depression than helplessness (Prociuk et al.,

Coping with coping concepts

Many concepts cover coping strategies and the expectancy attached to such responses.

Predictability, fear and anxiety

Predictability is used both for the true relations between events, and the subjective or learned (perceived) relation. Only the acquired (learned) relation is related to internal state of the organism. Perceived predictability offers formal definitions of fear and anxiety.

A highly probable, as well as a highly improbable, event are both predictable, and are concurrent with low arousal. Uncertainty produces high arousal. However, predictability in itself is not enough to predict the internal

Set values, expectancies, and access to the activation of the arousal system

Stress (alarm) occurs when something is missing, i.e. when there is a discrepancy between goals (SV) and reality (AV). The probability of eliminating such discrepancies influences access to the arousal system (Table 6

. Access to the activation system

Access to the activation and arousal system depends on the perceived probability of success
Low probability:
Statement 15: Activation→0 if SV1AV1, and if PP((SV1AV1)→0)→0
Statement 15 is to be read: For any particular motivational system with a

Activation and arousal theory

Stress is an adaptive response

The ability to respond to changes and challenges in the environment with a general alarm response should be regarded as an essential element in the total adaptive and self-regulating system of the organism (Levine and Ursin, 1991). Since arousal and ‘stress’ are essential elements in all complex brains—in fish, birds, and mammals—the activation response must be assumed to be ‘adaptive’. The response is uncomfortable and drives the organism to provide specific

Psychological defense

Stress may be reduced by distortion of stimulus expectancies.

Within traditional ego psychology or psychodynamic theory coping was one of many ways to defend (Haan, 1977). This is still influential in literature on stress, and in many animal studies. Toates (1995) defined stress as a ‘chronic state that arises only when defense mechanisms are either being chronically stretched or are actually failing’. To Folkman and Lazarus (1990) defense is a coping strategy.

Within ego psychology, the first

Sustained high levels of arousal and health

Only sustained high arousal levels constitute a potential health risk.

Weiss, 1968, Weiss, 1972 claimed that numerous coping attempts, in the absence of feedback, would result in stomach ulcers and a depletion of noradrenaline in the brain. We have regarded this as sufficiently analog to the situation in humans, as described by Karasek and Theorell (1990), to produce a composite figure comprising both sets of data (see Fig. 3). The model predicts disease, especially related to cardiovascular

Coping and social status

Social order is related to expectancies, coping and health.

In animals and human societies social order reduces hostility and conflict. Ptarmigans (willow grouse), an arctic bird, establish order during winter. The dominating male has low cortisol, high testosterone, high secondary sexual features, and lower body temperature than subordinate males. Once order has been established, fighting decreases. The catabolic stress responses decreases in the whole flock, most in the dominating male, but

Brain mechanisms

A prerequisite for the CATS position on stress is a general, non-specific brain stem activation concept.

The concept of arousal entered psychology from neurophysiology, with the documentation of a mesencephalic brain stem system for evoking and maintenance of wakefulness (Moruzzi and Magoun, 1949). The concept has been controversial, but seems to us to be necessary in physiological, psychological, and clinical science, in man and animals. In a Science commentary Steriade (1996) stated that it

Conclusions

CATS differs from many other approaches to ‘stress’ in the emphasis on the positive health consequences of the normal alarm response, occurring whenever the organism is lacking an essential factor. The theory is an expansion of general arousal and activation theory from neurophysiology. The stress responses are normal activation responses leading to an increase in arousal, and corresponding changes in behaviour as well as in most or all parts of the body. These somatic changes are mediated

Acknowledgements

The authors are grateful for research support from The Norwegian Research Council and the Norwegian Department of Health and Social Affairs. Many of our colleagues have helped with the manuscript and the development of the ideas behind it. In particular, we want to thank Jos F. Brosschot, Gary D. Coover, Seymour Levine, Robert Murison, Miranda Olff, J.B. Overmier, and Frederick Toates.

References (96)

  • N. Shanks et al.

    Alterations of central norepinephrine, dopamine and serotonin in several strains of mice following acute stressor exposure

    Pharmacol Biochem Behav

    (1991)
  • H. Ursin

    The psychology in psychoneuroendocrinology

    Psychoneuroendocrinology

    (1998)
  • H. Ursin et al.

    Habituation to electrical stimulation of the brain in unanesthetized cats

    Electroencephalogr Clin Neurophysiol

    (1967)
  • E.P. Zorrilla et al.

    High self-esteem, hardiness and affective stability are associated with higher basal pituitary-adrenal hormone levels

    Psychoneuroendocrinology

    (1995)
  • N.E. Adler et al.

    Socioeconomic status and health. The challenge of the gradient

    Am Psychol

    (1994)
  • A. Antonovsky

    Unraveling the Mysteries of Health: How People Manage Stress and Stay Well

    (1987)
  • B. Arnetz

    The potential role of psychosocial stress on levels of hemoglobin Alc(HbA1C) and fasting plasma glucose in elderly people

    J Gerontol

    (1984)
  • B. Arnetz

    Techno-stress: a prospective psychophysiological study of the impact of a controlled stress-reduction program in advanced telecommunication systems design work

    J Occup Environ Med

    (1996)
  • A. Bandura

    Self-efficacy mechanisms in human agency

    Am Psychol

    (1982)
  • R.C. Bolles

    Reinforcement, expectancy and learning

    Psychol Rev

    (1972)
  • C.L. Cooper

    Stress in the workplace

    Br J Hospital Med

    (1996)
  • G.D. Coover et al.

    Conditioning decreases in plasma corticosterone levels in rats by pairing stimuli with daily feedings

    J Comp Physiol Psychol

    (1977)
  • G.D. Coover et al.

    Plasma-corticosterone levels during active-avoidance learning in rats

    J Comp Physiol Psychol

    (1973)
  • A. Dickinson

    Expectancy theory in animal conditioning

  • R.A. Dienstbier

    Arousal and physiological toughness: implications for mental and physical health

    Psychol Rev

    (1989)
  • I.M. Endresen et al.

    Stress at work and psychological and immunological parameters in a group of Norwegian female bank employees

    Work and Stress

    (1991)
  • H.R. Eriksen et al.

    Subjective health complaints: Is coping more important than control?

    Work and Stress

    (1999)
  • H.R. Eriksen et al.

    Social inequalities in health: Biological, cognitive and learning theory perspectives

    Norsk Epidemiologi

    (2002)
  • H.R. Eriksen et al.

    A scoring system for subjective health complaints (SHC)

    Scand J Public Health

    (1999)
  • H.R. Eriksen et al.

    Effects of psychological defense on processing of neutral stimuli indicated by event-related potentials (ERPs)

    Scand J Psychol

    (2000)
  • H.R. Eriksen et al.

    The CODE: A revised battery for coping and defense and its relations to subjective health

    Scand J Psychol

    (1997)
  • S. Folkman et al.

    Coping and emotion

  • R. Glaser et al.

    The influence of psychological stress on the immune response to vaccines

    Ann NY Acad Sci

    (1998)
  • D.S. Goldstein

    Clinical assessment of sympathetic responses to stress

    Ann NY Acad Sci

    (1995)
  • J.A. Gray

    Elements of a Two-Process Theory of Learning

    (1975)
  • M.R. Gunnar et al.

    Dampening of adrenocortical responses during infancy: Normative changes and individual differences

    Child Dev

    (1996)
  • M. Gunnar et al.

    Low cortisol and a flattening of expected daytime rhythm: Potential indices of risk in human development

    Dev Psychopathol

    (2001)
  • K.M. Heilman

    Emotional experience: A neurological model

  • I. Hendrick

    The discussion of the ‘instinct to master’

    Psychoanal Q

    (1943)
  • J.A. Hobson et al.

    The Reticular Formation Revisited: Specifying Function for a Nonspecific System

    (1980)
  • N. Haan

    Coping and Defending

    (1977)
  • F.W. Irwin

    Intentional Behavior and Motivation

    (1971)
  • J.G. Johnson et al.

    Hopelessness as a mediator of the association between social support and depressive symptoms: findings of a study of men with HIV

    J Consult Clin Psychol

    (2001)
  • T.A. Judge et al.

    Are measures of self-esteem, neuroticism, locus of control, and generalized self-efficacy indicators of a common core construct?

    J Pers Soc Psychol

    (2002)
  • R.A. Karasek et al.

    Healthy Work, Stress, Productivity, and the Reconstruction of Working Life

    (1990)
  • S.C. Kobasa et al.

    Hardiness and health: a prospective study

    J Pers Soc Psychol

    (1982)
  • M. Kristenson et al.

    Attenuated cortisol response to a standardized stress test in Lithuanian versus Swedish men: The LiVicordia study

    IJBM

    (1998)
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