Download Classical Conditioning Methods in Psychotherapy

Classical Conditioning Methods in Psychotherapy
William C Follette and Georgia Dalto, University of Nevada Reno, Reno, NV, USA
Ó 2015 Elsevier Ltd. All rights reserved.
Abstract
Classical conditioning describes associative learning where stimuli are sometimes paired to produce clinical problems
including most anxiety disorders. Extinguishing problematic responses that arise through classical conditioning is the focus
of many psychotherapy procedures. This article describes the basic principles of classical conditioning, how understanding
these principles helped clarify our understanding of the etiology of clinical problems, and how exposure-based treatments
were developed to reduce or eliminate these problems. Recent cognitive explanations regarding the change process in humans
are described. Finally, some attempts to add pharmacological adjuncts to improve the efficacy of exposure are reviewed.
One of the most common reasons people seek psychotherapy is because of anxiety or fear about some situation or
object. There are many accounts for how these emotional
states develop, but when people present for therapy it is
often because their avoidance of these fearful situations
interferes with some aspect of their desired role functioning.
One of the most commonly used technical procedures in
psychotherapy is exposure, and it is particularly effective in
the treatment of these types of clinical presentations. The
effectiveness of exposure hinges primarily on an understanding of classical conditioning, also called Pavlovian or
respondent conditioning.
Classical conditioning is commonly defined as a process
whereby a previously neutral stimulus comes to exert control
over a response through pairing of the neutral stimulus with
a stimulus that naturally (i.e., with no prior training) elicits
the response. Since its accidental discovery by the Russian
physiologist Ivan Pavlov in the late-nineteenth century,
classical conditioning has been applied to many normal as
well as clinically significant behaviors such as those characterizing anxiety disorders and addiction. Using principles
derived from classical conditioning theory and contemporary
extensions of the theory, behavior therapies have been
developed to reduce the fear and anxiety responses that
interfere with normal functioning.
The Procedures and Processes of Classical
Conditioning
Classical conditioning is the most straightforward example of
associative learning where stimulus–stimulus associations
develop. According to the above description, the stimulus that
naturally elicits the response is known as the unconditional
stimulus (US), the naturally occurring response is known as the
unconditional response (UR), the previously neutral stimulus
is known (following conditioning) as the conditional stimulus
(CS), and the response that comes under the control of the CS
is known as the conditional response (CR). The process was
first outlined by Pavlov during his study of the salivary
response in dogs. Food in the mouth naturally produces
a salivary response to aid digestion, but Pavlov noticed that his
subjects began to salivate to the sound of a bell that accompanied the opening of the laboratory door during feeding time.
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In a series of now classic experiments, Pavlov demonstrated
that the bell became a CS for the food (US) and that the CR of
salivation was very similar to the natural salivary response (UR)
elicited by the food.
For the better part of a century, contiguity between CS and
US was commonly cited as an essential determinant of the
successful conditioning of a response. Optimal conditions were
said to be those in which the CS simply occurred immediately
before onset of the US. However, more recently, the focus has
shifted from contiguity between the CS and US to the amount
of information supplied by the CS about the occurrence of the
US (Rescorla and Wagner, 1972). For example, if a US occurs as
frequently (or more frequently) in the absence of the CS as in
its presence, very little conditioning will occur. The CS in this
case is simply a poor predictor of the onset of the US. To
exemplify the basic procedure by which a conditional response
to a previously neutral stimulus is established, consider the
following example. A small child with no fear of dogs is playing
near a dog’s food bowl. As the dog approaches, the unsuspecting child reaches out playfully to pet it. The dog (CS),
presumably guarding its food, nips the child (US), causing
minor tissue damage and producing a fear response in the child
(UR; e.g., crying, retreating, etc.). If the child emits a fear
response (CR) when next confronted with the sight of a dog
(CS) and in the absence of another nip, conditioning is shown
to have occurred. Earlier descriptions of classical conditioning
also stated that the CR was generally topographically similar to
the UR. That is, the CR looked the same. It is now recognized
that the CR may look different from the UR depending on the
species of the organism. In humans, the nature of the CR may
vary substantially from the UR.
Generalization and Discrimination
Two other processes are relevant to a discussion of classical
conditioning in clinical psychology: generalization and
discrimination. In stimulus generalization, the CR occurs to
stimuli that are similar in some way to the CS (but to which the
response has never been conditioned). If the child was bitten
by a Golden Retriever, but then comes to emit the fear response
in the presence of German Shepherds and Chihuahuas, stimulus generalization is said to have occurred. In nonverbal
organisms, generalization occurs on the dimension of some
shared property of the stimulus. For example, if a dog were
International Encyclopedia of the Social & Behavioral Sciences, 2nd edition, Volume 3
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Classical Conditioning Methods in Psychotherapy
classically conditioned to a tone of a certain frequency, then
similar sounding tones could also elicit a CR. In humans,
language allows other generalization to occur along dimensions that may share no formal properties with the original CS
but have acquired a relationship with the CS that can produce
a CR. For example, only humans can show conditioning to the
sight of a dog (CS) and also to the word ‘dog’ or the name
‘Rover’ or a leash, without prior conditioning once the animal
has become a CS. In stimulus discrimination, the CR does not
occur to stimuli that differ sufficiently from the original CS. In
this case, the child would only fear Golden Retrievers, and
would not emit that response to other breeds.
Exposure to the US or the CS: Habituation and Extinction
The process by which a fear response can be learned was
described above. This same response can also be inhibited. One
or both of the following processes can be used clinically to
reduce fear responding. The first process is called habituation
and it occurs through the repeated presentation of the US
without the CS. The CS comes to have no predictive value for the
occurrence of the US such that later presentations of the CS do
not elicit a CR. The other process that can lead to inhibition of
the CR is called extinction. Extinction is when the CS is presented
without an accompanying US. A tone may be presented to a dog
but food no longer follows. Eventually, the predictive value of
the CS is diminished such that the CS no longer produces a CR.
Classical Conditioning and Avoidance
in the Development of Psychopathology
The example of the child and the dog demonstrates the
potential for classical conditioning to play a part in the etiology
of a severe and persisting fear of dogs, or simple phobia, and it
identifies a pathway through which many other fear or anxiety
related disorders are thought to develop. Watson and Rayner
(1920), in their classic Little Albert experiment, effectively
conditioned fear in an infant. After allowing the child to play
with a white laboratory rat (to which he showed no previous
fear), the researchers followed presentation of the rat (CS) with
a loud bang on an iron bar behind Little Albert’s head. The loud
noise (US) elicited a startle response from the child (UR),
accompanied by crying. After a number of trials with this
pairing, Little Albert began to emit a fear response (CR) to
presentation of the rat alone, a response that also generalized to
other white, furry objects. The clinical significance of this
response (i.e., its persistence and the degree of functional
impairment it produced) is not known, as Little Albert did not
participate in follow-up studies and is thought to have died at
age six (Beck et al., 2009). However, one of Watson’s later
graduate students, Mary Cover Jones, did demonstrate that
phobic responses could be reduced by gradually exposing
a child to the feared object (Jones, 1924).
People can also learn fear responses without directly experiencing the CS–US pairing, but can instead learn through
observation. When someone observes a dog bite a person
resulting in injury and distress, the observer may acquire
a conditioned response. This is called vicarious learning. One
can acquire even more subtle associations such as when a child
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is holding a parent’s hand and notices a hand squeeze and
protective movement when the parent sees a strange, large dog.
Though many adults with specific phobias can recall a CS–US
pairing, a large number of such people have no such recall.
While it is possible that some of these reports are simply failures of memory, this also suggests that vicarious learning can
account for some proportion of episodes of conditioning.
Not all stimulus–stimulus relationships are equally easily
established (Garcia and Koelling, 1966). Certain modalities of
associations are learned more readily than others. For example,
pain is more readily associated with visual or auditory stimuli
than gustatory stimuli (Rachman, 1991). Conversely, internal
stimuli are more readily conditioned with gustatory stimuli.
Thus, it is common for taste aversions to be acquired after an
episode of nausea or vomiting (Bernstein, 1999).
Individual Differences
Not everyone who experiences a potentially traumatic event
will go on to demonstrate the pathological avoidance or
exaggerated startle responses characteristic of post-traumatic
stress disorder (PTSD), nor indeed does everyone exposed to
a fear-inducing US develop conditioned fear or a phobic
response to the accompanying CS. Again, classical conditioning
principles may help shed some light on this individual difference. The concept of ‘conditioned inhibition’ suggests that
when the CS is a compound stimulus (e.g., all the myriad
stimuli that make up the context in which an event occurs), the
stimuli that signal the absence of the US will inhibit conditioned responding. Consider the example of a child who is with
her mother when a bomb goes off on a bus. Because the
presence of the child’s mother has, through previous conditioning, come to signal safety (or the absence of danger), the
child may not develop a conditioned fear response to other
stimuli present at the time of the explosion (e.g., loud noises,
buses, etc.). In this case, the child’s mother has served as
a conditioned inhibitor and effectively protected the child from
developing a pathological fear response to the neutral stimuli.
The principles of stimulus generalization and discrimination can also help explain individual differences in psychopathology. When fears become pervasive (such as when a rape
victim comes to fear all men), it is likely due to extensive
stimulus generalization. Many things have come to participate
in a stimulus class with the original CS because they are similar
on some relevant dimension (e.g., they are all male). Alternatively, very circumscribed fears are the result of appropriate
stimulus discrimination (as when an individual avoids the
intersection at which he had a serious automobile accident but
is still able to drive through all other parts of the city).
Individual differences in reactivity to potentially fearinducing events also depend on the unique learning histories
of the individual. One way histories differ is in terms of prior
experience with stimuli. The Kamin ‘blocking’ effect states that
a stimulus that is part of a compound stimulus will fail to
produce conditioning if other stimuli in the compound have
already been conditioned (Kamin, 1969). A boy who has come
to emit a fear reaction at the sight of soldiers in uniform
because they were present when he arrived home to find that
his mother had been killed in an airstrike, may not come to fear
news reporters who are present (in addition to soldiers) when
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the rest of his family is killed in a similar attack 2 weeks later.
The blocking effect is thought to occur because the second
stimulus does not provide any new information about the US
beyond that supplied by the original CS.
Avoidance
If classically conditioned fear responses reduce on their own
when either the CS is presented without the US, or the US is
presented without the CS, then why don’t fear responses
naturally ameliorate? In fact, some do (Staley and O’Donnell,
1984). Epidemiologic studies do show that children endorse
a higher number of feared objects than do adults, though some
fears develop later (Merckelbach et al., 1996). What accounts
for the diminution of the feared objects as people get older?
The answer is likely natural exposure that occurs during the
course of childhood. If a child is showing a fear of a dog known
to be friendly, parents or the dog owner may well slowly
present the dog for petting by the child or may model petting
after which the child does the same. This kind of natural
exposure produces extinction and is likely why the prevalence
of specific phobias decreases over time.
What accounts for when fear responses persist? A version of
the answer was offered by O.H. Mowrer (1956) called twofactor learning theory. In its simplest form, the theory argues
that fear responses are classically conditioned in roughly the
way described above. It is the second factor that interferes with
the natural reduction in the fear response: avoidance. Avoidance occurs when someone begins to encounter either the
feared stimulus, the US, or stimuli that have become conditioned to elicit the feared response. As the fear rises, the person
avoids contact with either the CS or US. This avoidance
behavior is negatively reinforced, i.e., made more likely to
occur (see operant learning) by the reduction or removal of fear
or anxiety. The clinical implication of this avoidance is that the
person does not experience either habituation or extinction,
because the aversive stimulus in never repeatedly contacted so
that habituation or extinction would occur. Going back to the
simple example of the person fearful of dogs, when such
a person sees the dog from some distance away, a mild aversive
response may be noted. As the dog gets closer, the anxiety rises.
If the person turns around and exits the situation, the anxiety or
fear quickly reduces. This reduction in the aversive emotion
negatively reinforces avoidance. In the short run, the aversive
state is removed thereby strengthening the avoidance. Had the
person continued to approach to dog in spite of the growing
anxiety, the person would have come right up to the feared
object, the dog, and not have experienced a bite. If the
approach behavior continued in other episodes, the fearful
response to dogs would have habituated. Though Mowrer’s
original formulation has been extended to include cognitive
components to address how widespread avoidance of various
stimuli can become, its treatment implications are still generally relevant, as will be discussed below.
Exemplars
People with PTSD show exaggerated startle responses and
report intense fear reactions to many stimuli that were
present at the time of the original traumatic incident (e.g., the
sound of a helicopter for a combat veteran, the presence of
crowds for a survivor of a mass shooting, darkness or the smell
of alcohol for someone who was raped in an alleyway outside
a bar late at night). In all of these examples, previously neutral
stimuli have come to elicit a fear response very similar to that
elicited at the time of the trauma. The stimuli that elicit the
fearful response are external to the person.
Panic disorder (sometimes described as fear of fear) is
characterized by intense fear responses to interoceptive (as well
as external) cues such as a pounding heart, dizziness, shortness
of breath, sweaty palms, or symptoms that may have preceded
a full-blown panic attack in the past. In this case, the initial
(and extremely unpleasant) panic attack can be thought of as
the US, fear of dying may be the UR, the early symptoms or
environmental conditions as the CS, and the fear response as
the CR. Since panic attacks may be perceived as occurring
randomly, any aspect of the environment may become a CS as
might any unpleasant physical sensation.
In some cases, panic attacks may lead to the development of
agoraphobia, literally a fear of public (open) spaces, but clinically a fear of being in a public place where one feels trapped
or faces embarrassment should a panic attack ensue. The
person tries to identify situational cues that will allow him or
her to avoid a panic attack. Since the cues are difficult to detect,
the person generalizes those situations broadly and avoids
more and more activities that take place away from the relative
safety of one’s home.
Anxiety disorders in general rely on treatment components
that derive from classical conditioning models. An individual
with social phobia may learn to avoid all manner of social
interactions or performance situations, because characteristics
of these contexts have been associated with humiliating experiences in the past.
Certainly, addictive behaviors have many classically
conditioned elements to them. The sight of needles, drug
paraphernalia, the olfactory or visual cues, or the appearance
of another drug user may elicit cravings in alcohol, opioid, or
stimulant abusers.
Using Classical Conditioning in Psychotherapy
In addition to helping explain the etiology of many forms of
psychopathology, an understanding of classical conditioning
principles has given rise to several forms of behavioral
psychotherapy. Beginning with Mary Cover Jones, ‘counterconditioning’ involved the pairing of a feared stimulus with an
appetitive (desirable) stimulus such that the response to the
former was replaced with the response to the latter.
Sensitization
One line of therapy based on classical conditioning was
developed to reduce behaviors desired by patients but that were
recognized to be unhealthy or otherwise undesirable. One of
the more common examples can be found in the history of the
treatment of alcohol dependence where conditioned taste
aversions are used to treat this difficult problem. As with many
clinical problems, treatment can be understood from either
a classical or operant conditioning perspective (or both). One
Classical Conditioning Methods in Psychotherapy
treatment strategy has been to classically condition the taste or
smell of alcohol with nausea by using conditioned taste aversion procedures (Revusky, 2009; Lemere, 1987; Reily and
Schachtman, 2009). As mentioned earlier, gustatory–nausea
relations are more easily learned than some other sensory
modalities. Two procedures are most common. In one, after the
risk of alcohol withdrawal has been managed, the patient is
given a taste of a preferred alcohol followed by an emetic drug
(Lemere, 1987). Emetics induce nausea or vomiting. The
notion is that alcohol when paired with the emetic will produce
a response of nausea to the alcohol in the absence of the
emetic. A variation on this approach is the use of disulfiram
(AntabuseÔ) in alcohol treatment programs (cf Krampe et al.,
2011; Jørgensen et al., 2011; Alharbi and el-Guebaly, 2013).
Disulfiram is another commonly used drug that provides
a similar learning history. Disulfiram interferes with the normal
metabolism of alcohol resulting in a buildup of acetaldehyde.
This can lead to nausea, vomiting, dizziness, and other
unpleasant side effects when one drinks alcohol, thus creating
a conditioned taste aversion.
Alcohol treatment programs have also tried to use aversive
electrical stimulation paired with alcohol taste to create
a conditioned aversion to alcohol as well. There is less evidence
that the shock–alcohol pairing is clinically as effective when
compared to the emetic–alcohol pairing, though the limited
evidence is not consistent (Smith et al., 1997; Cannon et al.,
1981; Lamon et al., 1977). There have been ethical objections to conditioned aversive therapies (Nathan, 1985; Wilson,
1987), but some patients find them a better alternative than
other treatment programs or compared to continued addiction.
Conditioned aversion therapies have been applied to
a variety of behaviors, the consequences of which can have
deleterious effects for those who exhibit them, or for society.
Aversion therapy has been adapted to smoking, cocaine use,
sexual deviations including child molestation, and paraphilias,
to name some examples (Rachman and Teasdale, 1969).
Covert Sensitization
Though not purely involving classical conditioning procedures,
covert sensitization, also called covert conditioning, has been
used to treat maladaptive approach behaviors including but
not limited to problematic compulsions, sexual behaviors,
alcoholism, obesity, nail biting, and smoking (Cautela and
Kearney, 1986; Cautela, 1971). This procedure was developed
as an alternative to the application of aversive stimuli such as
an electric shock or an emetic (cf Krampe et al., 2011; Jørgensen
et al., 2011; Alharbi and el-Guebaly, 2013). Covert sensitization makes use of aversive imagery that may be easier to
produce outside of the laboratory or treatment environment. In
brief, the subject is taught to imagine himself as about to
engage in some desired but problematic behavior such as
taking a drink. Vivid cues are provided to enhance the image. As
the person is about to take the drink, he is instructed to imagine
an uncomfortable feeling taking over that results in a further
image of feeling profound nausea followed by vomiting. The
vomiting is imagined to result in vomiting on oneself, the
table, and perhaps others. The person is instructed to imagine
odors, being embarrassed, and perhaps other aversive consequences. This process is repeated. In some versions, the person
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may be taught to imagine being about to take a drink, feeling
the beginning of the nausea, and stopping, which is followed
by a feeling of relief and pride that one resisted the drink.
It is not easy to measure how well the covert stimuli are
produced or to assess how well or how willing one is able to
produce the aversive covert stimuli. Nevertheless, this procedure can be useful when one behaves under the control of
a reinforcer that is inappropriate or leads to undesirable
consequences.
Systematic Desensitization
Joseph Wolpe was among the first to use the term ‘systematic
desensitization’ for his approach to reducing fear responses to
anxiety-producing stimuli (Wolpe, 1961). In this treatment,
a relaxation response is trained in advance of exposure to the
feared stimulus. When the feared stimulus is introduced, the
client is instructed to engage in the relaxation response, which
is believed to be physiologically incompatible with the fear
response (Wolpe originally use the term ‘reciprocal inhibition’;
see Wolpe, 1958 for an early explanation of the intervention).
Typically, there are three steps to this treatment. One is to
identify a hierarchy of situations that are increasingly fearprovoking for the patient. In the case of acrophobia (a fear of
heights), the patient and therapist list a series of such scenes
from looking at a short step ladder to standing in front of this
ladder to stepping on the first step. Additional scenes are
constructed culminating with the most challenging scene that
might be standing on the ledge of a tall building and looking
down at the street below. In a commonly practiced version of
this treatment, the scenes are sorted from the lowest arousing
scene to the highest. Some number of sessions are used to teach
the subject relaxation skills. Once those skills are learned, the
therapist has the person imagine approaching the first element
of the hierarchy until they notice some uneasiness, at which
point they are told to use their relaxation skills until they
become comfortable. This is repeated until that element of the
hierarchy no longer produces anxiety or fear, and then the next
scene is presented. This process is repeated until the client
completes the hierarchy. Some have proposed that the process
involves extinction, while others suggest habituation takes
place (Watts, 1979). In either event, the previously avoided
stimuli are contacted and the anxiety response is sufficiently
reduced to allow normal functioning.
When treatment is designed as described above, it is often
experienced as more palatable for both the client and therapist.
As research has shown, it is not actually necessary for the
hierarchy of scenes to be presented in a particular order; nor is it
essential that the client have mastered a relaxation response;
and some data indicate that in vivo exposure to elements in the
hierarchy are perhaps more effective than imaginal techniques
(see Marks, 1978 for a review). Thomas Stampfl introduced the
technique of ‘flooding,’ in which the client is exposed to large
doses of the feared stimulus and prevented from escaping until
the fear response subsides (Stampfl and Levis, 1967).
Contemporary treatments such as prolonged exposure for
trauma and exposure and response prevention for obsessivecompulsive disorder (OCD) were built on this tradition of
harnessing the power of classical conditioning to replace maladaptive responses with more adaptive ones. What all these
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Classical Conditioning Methods in Psychotherapy
techniques have in common is that they involve exposing the
client to the feared stimulus instead of allowing him or her to
continue to avoid it.
Over the last 25 years, several difficult-to-treat problems
have been successfully addressed by creative exposure
procedures. Panic disorders have been treated by making use
of interoceptive exposure where some of the symptoms of
panic are produced but without the panic attack itself
(Barlow et al., 1989; Barlow and Craske, 1989). Many who
experience panic attacks become hypersensitive to normal
physiological responses such that when they occur, fear of
a panic attack ensues. In interoceptive exposure procedures,
a variety of exercises are used to bring about some of those
internal sensations so that the fear of a panic attack does not
occur when some cues occur. For example, patients are
taught to hyperventilate to experience some lightheadedness.
Similarly, a patient may sit on a chair that spins around
sufficiently to induce mild dizziness. A variety of exercises are
utilized to expose patients to bodily cues that do not become
panic attacks.
OCD is another clinical problem that has been usefully
treated by exposure and response prevention (Franklin and
Foa, 2011). In OCD, patients are exposed to that about
which they obsess and are prevented from exhibiting the
compulsive behavior that they use to reduce the obsessions. For
instance, someone who obsessed about germs might be
exposed to a dirty article of clothing for long periods of time
and not allowed to wash his hands.
Debate exists with regard to the mechanisms by which
exposure reduces fear and anxiety (McSweeney and Swindell,
2002). Traditionally, this process has been described as
extinction, whereby the CR fails to occur following repeated
presentation of the CS without the US. The CR is said to
extinguish as a result of this procedure. The idea is that the link
between CS and US is severed, so that the CS no longer predicts
the US. According to Rescorla–Wagner model, this procedure
would diminish the information about the US provided by the
CS. However, McSweeney and Swindell (2002) examined the
substantial body of literature available at the time and
concluded that there is considerable evidence to suggest that
the process known as extinction actually relies on the even
more basic principle of habituation. Habituation is defined as
“a decrease in responsiveness to a stimulus when that stimulus
is presented repeatedly or for a prolonged time” (p. 364–365).
When applied to the senses, habituation is known as ‘sensory
adaptation’ and it is a process so pervasive that we often take it
for granted (consider the experience of walking into a room
with a strong offensive odor and suddenly realizing half an
hour later that you can no longer smell it). The case presented
by McSweeney and Swindell suggests that repeated or prolonged exposure to the CS will cause a decrease in the probability or likelihood of the CR through this process of
habituation. It remains an empirical question whether habituation occurs to the CS through repeated or prolonged exposure even when the CS continues to be followed by the US.
Treatments based on classical conditioning principles also
consider such effects as stimulus generalization and discrimination, blocking, and conditioned inhibition. The tendency of
fears to generalize to additional stimuli can make treatment
challenging, as many more stimuli than those involved in the
original fear-inducing event may need to be targeted in treatment. On the other hand, one expects that treatment produces
new learning (i.e., to not fear the stimuli used in exposure) that
will generalize to additional feared stimuli.
However, the situation is complicated, as habituation and
extinction appear to generalize less readily than the original
conditioning (McSweeney and Swindell, 2002). Stimulus
discrimination can be encouraged by training the individual to
distinguish between the original feared stimulus and similar
(but different) stimuli. This process may help prevent the
generalization of the fear response following the original
conditioning event. Blocking could potentially prevent new
learning from occurring such that it may be more effective to
conduct exposures to one feared stimulus at a time; pairing
a reconditioned stimulus with one that is still feared may
render the still feared stimulus redundant (i.e., it does not
provide any new information about the situation).
The impact of conditioned inhibition on psychotherapeutic techniques informed by classical conditioning may be
more complicated. While the presence of a stimulus that has
come to signal safety may protect the individual from fear
conditioning to begin with, such ‘safety signals’ may also
impede the process of extinction/habituation during exposure.
It is thought that safety signals (such as empty medication
bottles or being accompanied by a significant other during
exposure exercises) prevent the individual from fully contacting the feared stimulus so that when exposed to the stimulus
in the absence of the safety signals, any apparent positive
effects of the exposure disappear.
Cognitive Considerations
Certainly, exposure-based therapies are among the most robust
intervention for the treatment of anxiety disorders. Exposure
relies on some aspects of classical conditioning principles
augmented by an operant understanding of the role of avoidance in the maintenance of anxious or fearful response. Two
observations have stimulated theorizing about a cognitive
explanation for how exposure works. First, not everyone who
undergoes an exposure-based treatment shows improvement
(Choy et al., 2007). This implies that our understanding of the
dimensions of the CS or CR is not fully adequate. Second, the
treatment of two difficult clinical problems, PTSD and OCD,
has engendered theorizing about what happens in humans
who can verbalize their experiences (Foa and Kozak, 1986). In
PTSD, a wide variety of stimuli, not easily categorized, can
produce fearful responding. In OCD, obsessions are cognitions
and patients provide elaborate explanations for the source of
the obsessions and the functions of the compulsions.
One of the more elaborated information processing/
cognitive models was called emotional processing theory (EPT)
(Foa and Kozak, 1991; Foa et al., 2006). EPT suggests that
effective treatments for fear and anxiety, including exposure,
produce their effects by introducing accurate information to
alter existing, or create new, fear structures. A fear structure
contains memories about sensory information about the feared
situation, the avoidance behaviors and one’s reactivity to the
situations, and information about the interpretations relating
the stimuli and responses. The basis of the prolonged exposure,
an effective but not the only treatment for PTSD, is that fear
Classical Conditioning Methods in Psychotherapy
structures associated with the traumatic memory entail
incorrect associations between stimuli and responses during
the trauma and its subsequent meaning. The set of stimuli
recognized and responded to as dangerous is too broad,
meaning that fear is experienced to a wider set of stimulus
conditions. The person also understands their responses as
incompetent in indicating they cannot cope. This results in an
inability to take in new experiences that would alter their
emotional processing. Prolonged exposure putatively works by
promoting alterations of the fear structures through systematic
confrontation of trauma related stimuli (using imaginal
exposure) with discussion of the experience in order to help
disconfirm the problematic beliefs. The result is the modification of the problematic fear structure or the creation of another
more adaptive one.
Not everyone agrees with the need for or the accuracy of this
conceptualization and some suggest genetic and individual
difference variables warrant attention in addition to remaining
aware of advances in associative learning (e.g., Mineka and
Thomas, 1999; Mineka and Oehlberg, 2008). In either case,
as the verbal constructions of the fear-evoking stimuli get more
elaborated, so too does theorizing. This perhaps follows from
the natural language patients use to discuss fearful situations
and responses to them, as well as the Rescorla and Wagner use
of the concept of information contained in the relationship
between the CS and US, again a use of language that promotes
a more mentalistic interpretation of emotional responding and
its treatment.
Future Directions
New technologies such as virtual reality are being applied to
simulate in vivo exposure to otherwise difficult-to-create stimulus conditions (see Virtual Reality in Psychotherapy). For
example, virtual reality goggles and sounds have been used to
present combat situations for those who show clinically
significant fear and anxiety responses following wartime
experiences. This same technology has been used to present
cues for high-risk situations such as gambling opportunities
and smoking situations where the cues themselves may be
conditional stimuli for these inappropriate behaviors or
discriminative stimuli from an operant learning perspective.
Virtual reality scenarios can be programmed for the treatment
of generalized anxiety disorder where many different kinds of
stimuli can elicit anxiety. Increasingly, technology is expanding
into the therapy environment.
It is clear from the principles of change purported to
underlie many of the empirically supported treatments for
anxiety that classical conditioning principles have contributed significantly to the arsenal of interventions currently
available to psychotherapists. However, the field would
likely benefit from the further explication of the precise
mechanisms that account for the improvements seen with
these therapeutic techniques. Among these are the issue of
whether extinction is a distinct process from habituation,
how the unique learning history of the client can assist or
impede treatment, and the extent to which classical and
operant conditioning interact both in the etiology and the
resolution of psychopathology.
769
Interesting pharmacologic interventions that possibly affect
mechanisms of memory (re)consolidation are currently being
researched. There is some evidence that propranolol,
a b-adrenergic blocker, may reduce PTSD symptoms, but the
ethics of such interventions have been debated (Donovan,
2010). There is evidence that the extinction of fear is mediated in the basolateral amygdala by the activation of N-methylD-aspartate (NMDA) receptors. The drug D-cycloserine can
indirectly enhance that activity and has been shown to enhance
fear extinction in exposure procedures in both animals and
humans, though that effect may only be present if fear is
lowered during a session (Smits et al., 2013). Given the ubiquity of anxiety disorders and the public health costs in terms of
treatment, resource utilization, and lost productivity, it is likely
that procedures to make extinctions procedures more available
and cost-effective will continue to evolve.
See also: Behavior Therapy: Background, Basic Principles, and
Early History; Exposure Therapies and Stress Inoculation: A
Brief Overview; Obsessive-Compulsive Disorder across the Life
Span; Panic Disorder and Agoraphobia Across the Lifespan;
Phobias Across the Lifespan; Reinforcement, Principle of;
Social Phobia across the Lifespan; Virtual Reality in
Psychotherapy.
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