A number of psychological principles based in leaning theory
have been extended to pain. These principles provide helpful explanations
for many clinical observations. Moreover, a number of cognitive
and affective factors have been demonstrated to influence expressions
of pain and participation in rehabilitation. We can consider the
major psychological, sociocultural, and behavioral principles and
factors studied and then consider how they can be integrated to
create a comprehensive model of pain that can serve as a guide for
assessment and, ultimately, treatment.
As long ago as the early part of the twentieth century, the effects
of environmental factors in shaping the experience of pain were
acknowledged. A new era in thinking about pain began in 1976 when
Fordyce3 extended the principles of operant conditioning
to chronic pain and disability.
In the operant conditioning formulation, behavioral manifestations
of pain rather than pain per se are central. When a person experiences
noxious sensation, the initial response is a withdrawal or escape
response. This may be accomplished by avoidance of activity believed
to cause or exacerbate pain, help-seeking to reduce symptoms, and
so forth. These behaviors are observable and, consequently, subject
to the principles of operant conditioning, namely, reinforcement
and avoidance learning.
The operant view proposes that pain behaviors, such as avoidance
of activity to protect a wounded limb from producing additional
noxious input, may come under the control of external contingencies
of reinforcement (responses increase or decrease as a function of
their reinforcing consequences). It is these reinforcement contingencies
that contribute to the maintenance of the problems associated with
chronic pain and disability. Pain behaviors (e.g., limping, grimacing, and
inactivity) are conceptualized as overt expressions of pain, distress,
and suffering. These behaviors may be positively reinforced directly,
for example, by attention from a spouse or from health care providers.
Pain behaviors also may be maintained by the escape from noxious
stimulation through the use of drugs or rest, or the avoidance of
undesirable activities such as work. In addition “well
behaviors” (e.g., activity, working) may not be positively
reinforcing, and the more rewarding pain behaviors may, therefore,
We can illustrate the role of operant factors in a case of chronic
back pain. When a woman with a painful back has a flare-up, she
may lie down on the floor and hold her back. Her husband will notice
these behaviors and infer that she is in pain. The husband’s
behavioral response is influenced by his observation of her behavior.
He typically responds to her pain complaints by spending extra time
and massaging her back. In this case, her lying down has resulted
in the pain sufferer receiving attention from her husband, a positive
consequence. According to the laws of operant learning, behaviors
that result in a positive consequence are more likely to recur.
Another powerful way the husband reinforces his wife’s
pain behaviors is by permitting her to avoid undesirable activities.
When observing his wife lying on the floor, the husband suggests that
they cancel their plans to get together with his brother that evening.
If the pain sufferer would prefer not to spend time with her husband’s
brother, then the avoidance of the undesirable activity is reinforced
and may contribute to reports of pain whenever activities with her
husband’s brother are planned. In this situation, her pain
reports and behaviors are rewarded both by her husband providing
her with extra attention and support, and by the opportunity to
avoid an undesirable social obligation.
It is important to clarify that the operant learning does not
require the pain sufferer’s intentional and conscious efforts
to elicit a desirable outcome. It results from a gradual learning
process that neither the sufferer nor others recognize. One should
not assume pain behaviors are synonymous with malingering. Malingering
involves the patient consciously and purposely faking a symptom such
as pain for some gain, usually financial. In the case of pain behaviors,
there is no suggestion of conscious deception; rather, the unintended
performance of pain behaviors results from laws of learning based
on environmental reinforcement contingencies. Typically, there is
little awareness that these behaviors are being displayed or that
the patient is consciously motivated to obtain a positive reinforcement
from the behaviors. The pain behavior in response to initial injury
may encounter reinforcing events, thereby determining probability
of that behavior recurring in the future. Once the behavior is learned,
the presence of initial pain is no longer needed for that behavior
The operant conditioning formulation does not concern itself
with the initial cause of pain. Rather, it considers pain an internal
subjective experience that can only be indirectly assessed and may
be maintained even after an initial physical basis of pain has resolved.
Because of the consequences of specific behavioral responses, it
is proposed that pain behaviors may persist long after the initial
cause of the pain is resolved or greatly reduced. Thus, in one sense,
the operant conditioning model can be viewed as analogous to the
psychogenic models described earlier. That is, psychological factors
are treated as secondary, reactions to sensory stimulation, rather
than directly involved in the perception of pain per se.
The operant view has generated what has proven to be an effective
treatment for select samples of patients with chronic pain.4 Treatment
focuses on eliminating pain behaviors by withdrawal of attention
and increasing “well behaviors” (e.g., activity)
by positive reinforcement. Although operant factors undoubtedly
play a role in the maintenance of disability, exclusive reliance
on the operant conditioning model to explain the experience of pain
may not be appropriate. It has been criticized for its exclusive
focus on motor pain behaviors, failure to consider the emotional
and cognitive aspects of pain, and failure to treat the subjective
experience of pain.5
Factors contributing to chronicity that have previously been
conceptualized in terms of operant learning may also be initiated
and maintained by classical or so-called respondent conditioning.6,7 If
an aversive stimulus is paired with a neutral stimulus several times,
the neutral stimulus will come to elicit aversive experience in
the individual. The patient leans to anticipate negative consequences
even in the absence of the noxious stimulus. This process has been
observed frequently in cancer patients receiving chemotherapy. Patients
have been observed to report nausea, even before any cytotoxic medication
has been administered, when they enter the room where they have
received chemotherapy. Similarly, a patient with back pain who received
a painful treatment from a physical therapist may become conditioned
to experience a negative emotional response to the presence of the
physical therapist, to the treatment room, and to any stimulus associated
with the nociceptive stimulus (e.g., exercise equipment). The negative
emotional reaction may lead to tensing of muscles and this, in turn,
may exacerbate pain, thereby reinforcing the association between
the presence of the physical therapist and pain.
The most relevant emotional conditioning in pain probably is
anxiety. Anxiety is often the affect underlying avoidance of activities.
Pain patients often experience temporary aggravation of pain following
physical activities. Avoiding such activities leads to no pain exacerbation,
thus reinforcing inactivity and maintaining anxiety for activity.
In other words, the persistence of avoidance of specific activities
reduces disconfirmations that could provide corrective feedback.8 Insofar
as avoidance does not produce disconfirmation, the behaviors will
persist.9 By contrast, when the anticipated consequence
does not occur (disconfirmation), modification of learning also
takes place. Thus, the physical therapist may have to encourage
the patient to exercise to provide disconfirmation of the anticipation
that exercise will hurt and lead to increased injury. The therapist
has to emphasize that hurt and harm are not the same things. Both
respondent conditioning and operant learning may contribute to the
development and maintenance of dysfunctional behavioral patterns
in patients with chronic pain. Over time, more and more activities, people,
and physical locations may be seen as eliciting or exacerbating
pain and will be avoided (stimulus generalization). Fear of pain
and avoidance may become conditioned to an expanding number of situations
(response generalization). In addition to the avoidance learning,
pain may be exacerbated and maintained in these encounters with
potentially pain-increasing situations because of the anxiety-related
increases in sympathetic activation and muscle tension that may occur
in anticipation of pain and, also, as a consequence of pain. Thus,
as we emphasize later in this chapter, psychological factors may
directly affect nociceptive stimulation and need not be viewed as
only reactions to pain.
Social learning has received some attention in the study of acute
pain and the development and maintenance of chronic pain states.
From this perspective, how we experience pain is shaped and influenced
by what we have observed, so-called observational learning. That
is, individuals can acquire responses that were not previously in
their behavioral repertoire by watching others perform these activities.
Children acquire attitudes about health, health care, and the perceptive
style for recognizing and understanding bodily symptoms from their
parents and social environment. They also learn how injuries and
diseases should be attended. As they grow older, the learning emerges
as their tendency to ignore or over-respond to symptoms they experience.
The culturally acquired interpretations of symptoms determine how
people deal with illness.
There is ample experimental evidence of the role of social learning
from controlled laboratory pain studies and some evidence based
on observations of patients’ behaviors in field and clinical settings.
Physiologic responses to pain stimuli may be conditioned during
observation of others in pain. For example, patients on a burn unit
have sufficient opportunity to observe the responses of other burn
patients.10 Each patient’s response to
his or her situation is affected by observations of other patients.
In one study, children of chronic pain patients chose more pain-related
responses to scenarios presented to them than did children of healthy
or diabetic parents. Moreover, teachers rated the children of pain
patients as displaying more illness behaviors (e.g., complaining, absences
from school, visits to the school nurse) than the children of healthy
controls.11 Expectancies as well as actual behavioral
responses to noxious stimuli are based, at least partially, on prior
social leaning history. This situation may contribute to the marked
variability in response to objectively similar degrees of physical
pathology noted by health care providers.