Facing Our Fears: Extinguishing Conditioned Fears with Exposure Therapy

Written By Alex Tansey

Alex Tansey

Illustrations by Ella Larson


You wake up one Sunday morning, ready for a productive day of studying. Everything is just right; the smell of freshly-brewed coffee wafts from your mug, your laptop is charged and ready to go, and your favorite album plays through your headphones. Then you see it. No more than ten feet away, a tiny, fuzzy black speck crawls across the floor. It’s heading right towards you! As it moves closer and closer, your heart begins to race at a million miles per second, sweat streams from your palms and forehead, and your chest tightens. You throw the heaviest book you can find at the tiny spider as you flee from the room crying for help.

These moments of utter panic are common for someone who suffers from arachnophobia, the clinical term for a fear of spiders. Arachnophobia is just one common fear that people can develop, but it is possible to have a fear of virtually anything; for instance, many people fear confined spaces, snakes, or public speaking. For some individuals, these fears can be intense and debilitating, causing anxiety that interferes with work, social life, and general wellbeing. Psychologists can help to reduce these negative effects of anxiety through a treatment known as exposure therapy, in which individuals are repeatedly exposed to objects and situations they fear without being harmed by them, thus learning that there is no true threat. Those who try exposure therapy may find that the anxiety returns with time, or when encountering their fear in a new place. It is therefore crucial to explore how to reduce the possibility of the anxiety returning. This can be accomplished by adapting exposure therapy so that it translates to broader scenarios in the real world. To maximize the effectiveness of exposure therapy for anxiety disorders, treatment needs to be altered to include a greater number and variety of environments where an individual may encounter fearful stimuli.

Anxiety, Fear, & Why Hiding From Spiders Won’t Work Forever

To explore how to most efficiently treat anxiety disorders, we must first understand its symptoms and triggers. Anxiety disorders are characterized by excessive, persistent fear and anxiety leading to emotional distress and impaired functioning [1]. Fear is defined as the emotional reaction to a perceived real or imminent threat, while anxiety is a reaction to the anticipation of a future or hypothetical threat [1]. For example, you may experience fear when you see a spider next to your bed, but you may feel anxious for the next few days when it escapes and you are waiting for it to return. Anxiety can be temporarily reduced via avoidant behaviors, like sleeping on the couch in the living room, in order to avoid encountering the spider. Avoidant behaviors can prove to be detrimental to one’s life, as they add stress and limit a person’s ability to accomplish everyday tasks. In the long run, avoidant behaviors fail to address the root of your anxiety; two or three weeks after seeing the spider in your room, the anxiety-inducing association between the spider and your bedroom may linger. This is because of a difficult-to-break phenomenon known as fear conditioning.

Fear conditioning is the framework through which anxiety-related disorders can develop. This concept is a form of Pavlovian conditioning, which occurs when an animal or human subject learns to associate an unconditioned stimulus with a conditioned stimulus [2]. The unconditioned stimulus can be any object, environment, or event which elicits a natural response in the subject. For instance, if you see your favorite food at a buffet, your mouth might start to salivate — the salivation is your natural response to the unconditioned stimulus (i.e. food). The conditioned stimulus, on the other hand, is something that becomes linked with the unconditioned stimulus, eventually causing the natural response by association. Fear conditioning is defined by when this conditioned stimulus, like the unconditioned stimulus, induces fear [2]. One infamous example of fear conditioning in humans is the Little Albert experiment, in which a toddler learned to associate a lab rat, the conditioned stimulus, with a loud and scary sound, the unconditioned stimulus; eventually this association caused the toddler to fear the rat itself [3]. The loud sound is the unconditioned stimulus as it caused a natural reaction in Albert. The rat is the conditioned stimulus because it only elicited fear in Albert once he learned to associate it with the scary sound. As Albert heard the loud sound, his amygdala –– a brain region involved in emotions, social learning, and memory –– was activated, causing Albert to associate the rat with fear and then consolidate that memory to make it more stable [4, 5]. 

Once a conditioned fear is cemented in your memory, breaking the association between the two stimuli can be incredibly difficult. This is where extinction becomes useful. The goal of extinction is to attenuate the learned relationship between the conditioned stimulus and the unconditioned stimulus. Extinction occurs through the repeated presentation of the conditioned stimulus by itself, not followed by the unconditioned stimulus [6]. For example, a therapist treating a patient with arachnophobia may repeatedly present their patient with a spider in a controlled, safe manner so that the patient can learn that there is no threat. Using fear extinction to treat anxiety disorders in a therapeutic context is called exposure therapy [6]. As exposure to a spider may feel unmanageable for those with arachnophobia, people can be exposed to their distressing stimulus in increasingly intense stages in order to help them feel more comfortable. Rather than jumping straight into using a real spider in therapy sessions, a therapist may begin by presenting their patient with a photo of a spider, followed by live spiders from a distance, then spiders up close, until they are eventually comfortable enough to hold a spider in their hand. If someone with arachnophobia is exposed to a spider multiple times and consistently experiences no harmful consequences, they will begin to form a new associative memory encoding spiders as safe  [7, 8]. Their amygdala would then work to stabilize this new association into long-term memory [5]. 





Fears Don’t Remain Quite As Extinct As the Dinosaurs

After weeks of observing and touching spiders in your therapist’s office, you finally feel like your arachnophobia is fading. That is, until you return home one night to see a spider sitting right in the middle of your bedroom. The fear floods back. Had all of those weeks in therapy been fruitless? It is important to note that extinction and exposure therapy are context-specific; while an arachnophobic individual may have felt less fear in the therapy room context, the fear may return if they are exposed to a spider in the wild. The hippocampus, a brain structure known for its role in memory, plays an important part in this contextual aspect of fear, as it is involved with remembering when and where an aversive experience occurred [9, 10, 11]. The context-specificity of exposure therapy makes it difficult for the development of long-term benefits. Fear can return when in a new environment because, despite its name, extinction does not actually erase the original fear [12]. Rather, extinction only provisionally suppresses fear, and may not work well in contexts other than that of the practice sessions. The phenomenon known as renewal demonstrates that a seemingly-extinguished fear can return when outside of the extinction context [12]. Imagine that Little Albert went through exposure therapy enough times in the lab without a loud sound for him to learn that the rat is no longer a threat. If he were to then see a rat in a different context, such as in his house, his fear may return. The specificity of context-dependent extinction thus causes many people who go through exposure therapy to experience relapses of their fear and anxiety when they encounter the stimulus in a new place.

Relapses of fear following exposure therapy are based on activity in the prefrontal cortex and the hippocampus — the two brain regions largely responsible for the retrieval of extinction learning. The prefrontal cortex aids in the recall of extinction learning over time, reducing the chances that your fear returns spontaneously [13]. Conversely, activity in the hippocampus can hinder extinction learning; hippocampal activity strengthens the connection between extinction training and environment, increasing the chances that the fear will return outside of the original extinction context [10, 11, 9]. This high likelihood of fear renewal following exposure therapy underscores the need to adapt therapy to be efficacious both in the long term and in many different environments. Such an adaptation may be possible via a process known as generalization. 

Generalization of extinction learning is necessary for exposure therapy to work outside of the therapeutic context. The Little Albert experiment not only exemplified fear conditioning but also demonstrated the phenomenon of stimulus generalization, or the ability to learn from a specific experience and apply that learning to similar situations [3, 2]. Little Albert reacted with fear not only towards the rat but also generalized his fear towards other vaguely rat-like objects and animals, such as fur coats and rabbits. This may be beneficial in some cases as it allows us to learn from aversive experiences and avoid them in the future. Yet, the Little Albert experiment shows that over-generalization of fear-inducing stimuli causes harmful anxiety when there is no actual threat present [2]. Generalization of extinction learning can be used to combat anxiety by increasing the number of environments in which fear is reduced. Using a variety of contexts and stimuli in exposure therapy increases the number of characteristics associated with extinction. This expands the quantity of situations that extinction learning can generalize to [14]. Exposure therapy is most effective when the learning can be applied beyond the therapy room itself due to the ever-changing nature of the real world. So how can we design and access a variety of therapy contexts without having to travel to different places or refurbish the therapist's office? The answer may lie in virtual reality (VR) technology. 






Extinguishing Real-World Fears in Virtual Environments

While you may only associate VR with epic new video games or avant-garde art exhibits, this technology is actually incredibly useful for exposure therapy as it can provide a wide range of contexts and stimuli not otherwise accessible; when participants practice exposure in a broad scope of scenarios it may increase the generalizability of the treatment. You might be thinking: won’t our brains know that the environment is fake? While it may seem like we are exceptionally talented at distinguishing reality from the virtual world, our brains actually respond very similarly to movements and perceptual changes in virtual environments as they do in reality [15]. Panoramic virtual environments elicit emotional and physical reactions and are therefore effective tools for measuring reactions to real environments [16]. Exposure therapy using VR has already been shown to be as effective as real-life exposure in reducing specific phobias and agoraphobia, or fear of places in which one may feel panic or embarrassment [17]. 

In one case, a patient sought therapy for a debilitating fear of sharks. Clearly, obtaining a live shark, bringing it inside a therapist’s office, and safely exposing it to the patient would be practically impossible. Instead, the therapist provides the patient with a virtual body of water to “swim” in [18]. As the patient swims, the therapist makes a 3D model of a shark move close to the surface. As soon as the patient expresses excessive anxiety, the therapist makes the shark retreat, and reappear when the patient’s anxiety has diminished enough that they are ready to try again. Many other anxiety disorders, such as fear of flying, fear of blood, or fear of injury, are difficult or impossible to treat with real-world equivalents.VR technology truly expands treatment possibilities by conveniently reproducing a wide variety of contexts and stimuli. 

The VR shark experiment used a variety of virtual environments, including an outdoor swimming pool, a lake complete with fish and moving water, and a sandy beach in order to increase the effectiveness of therapy [18]. Rather than using just one environment, multiple extinction contexts like these can increase the generalizability of extinction learning. For instance, exposure to a real-life spider in multiple extinction contexts reduces fear renewal for people who are highly anxious of spiders [19, 20, 21]. Numerous extinction sessions, long-term exposure practice, and the incorporation of exposure environments similar to the initial fear acquisition context all improve this intensity of this effect [22, 23, 24]. Thus, multiple surroundings are essential to extinction training in order to reduce the chances of fear or anxiety relapse. This relapse could occur when the patient is exposed to the conditioned stimulus somewhere other than the place where the patient first became afraid. Similarly in virtual exposure therapy, exposure to a virtual fear-inducing stimulus in different virtual extinction contexts successfully reduced chances of fear relapse [25, 26]. Studies like this and the shark study take advantage of the freedom that VR can give to easily adjust realistic contexts. VR may prove exceedingly useful in an everyday clinical setting as well. 

VR can be utilized not only to increase the availability of contexts in exposure therapy, but also the options for stimuli, in order to improve the generalization of exposure therapy. For example, exposing someone with arachnophobia to multiple types of virtual spiders may be more effective at reducing fear in comparison to just using one type of spider. This has been supported in a real-world lab setting, as those exposed to four different real-life tarantulas showed reduced fear in the long term in comparison to those exposed to only one [27]. However, it may be unrealistic or unsafe for therapists to have access to live spiders in their sessions. VR is therefore a much more viable alternative for deploying multiple stimuli, successfully leading to a long and short term reduction of fear [28]. This method of increasing generalization could be applied to other phobias by using virtual stimuli such as different animal species, people, and heights. Though, there does not seem to be any special benefit to incorporating both context cues and stimulus generalization simultaneously [28]. This could be due to expectancy violation theory, in which extinction learning has a stronger effect when there is an unexpected occurrence in comparison to when there is an expected occurrence [28]. Imagine you enter a familiar room and see a spider; you would naturally be more surprised than if you are going into a completely new room and encounter a spider. While both a variety of contexts and a variety of stimuli may increase the success of exposure therapy, therapists may need to focus on only one of the two methods. Further study should explore which of the two treatments is more effective depending on specific patient needs.

Future VR studies should also distinguish a means to incorporate other sensory elements such as touch and smell, which may be important in order to translate more realistically to real-world contexts and triggers. One case study did successfully incorporate tactile elements, in which a spider-phobic patient could touch a physical replica of a spider during virtual exposure sessions [29]. Including other sensory elements consequently elevates the realism of virtual exposure. VR is indeed a fascinating field to expand the possibilities for what can be accomplished within a single therapy space. It can be used as one of the first steps of exposure to distressing stimuli prior to more invasive real-world exposures. 

We’re No Longer Doomed to Fearful Fates

Exposure therapy is a go-to treatment for anxiety disorders, and while it is beneficial, improvement is needed in order to maximize its effectiveness in the long term. By introducing a greater number of contexts and stimuli during exposure training, extinction learning will be able to generalize towards a more diverse amount of real-world scenarios, decreasing anxiety beyond the controlled lab environment. Since gaining access to these environments and stimuli may not always be feasible, VR fills that gap to provide an extended amount of realistic virtual environments for patients to explore. VR may also encourage more people to seek help for phobias, as it may feel more approachable to know that what they are being exposed to is not real. In fact, it has been found that more people report willingness to do VR exposure therapy than in-vivo exposure therapy [30, 31]. Perhaps this new technology can be an incentive for more people to seek and benefit from exposure therapy. And maybe when you find yourself confronted with that little black spider next time, you can think back to this article and remember he wasn’t so dangerous after all.

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Alex Tansey
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