Treatment and environments

This chapter will describe why the two specific methods were chosen. One method to treat the people suffering from acrophobia, and one method to build the environments needed in the treatment of acrophobia. The final section of this chapter will give a list of requirements.

Development of a phobia

There are three theories about how people develop phobias: Behavioral theory suggests that the anxiety is a conditioned response to a specific stimuli. These anxieties can be gotten from a bad experience or learned from someone else, parents for example. These can be treated by repeated exposure to the stimulus.

In the biological theory, the phobia is represented in the brain as a biological entity. Some combination of different chemicals and hormones can affect a part of the brain when the person experiences anxiety.

Existential theory provides a model for generalized anxieties. These are disorders where there is no specific stimulus that causes the anxiety disorder. Central to this theory is that the subject becomes aware of a profound nothingness in his life.

The most commonly used theory is the behavioral theory [kaplan 91]. This theory is the most studied and used theory for treatments of phobias. Because it is the most studied and used theory, it also gives the best description of how to use the theory. This makes it easier for us to use it when treating people with Virtual Reality. The following sections will describe some of the most commonly used treatment schedules based on behavioral theory.

The other theories are also used to develop treatments, sometimes more than one method is used to develop a treatment [michelson 85] and [pollard 87].

Treatment based on behavioral theory

Behavioral theory has different groups of treatment. The following sections will explain the following six treatments. Besides these treatments, there are many more treatments developing and developed [watkins 88] and [michelson 84].
  1. systematic desensitization
  2. graded exposure
  3. flooding and implosion
  4. participant modelling
  5. assertiveness and social skill training
  6. aversion therapy / positive reinforcement.
The following sections will each explain one of these treatments. These descriptions were taken from Synopsis of Psychiatry: Behavioral Sciences, Clinical Psychiatry [kaplan 91].

Systematic desensitization

Systematic desensitization consists of cycles of the following steps: the subject has to relax. When he is relaxed, he has to imagine the stimuli that causes a mild form of anxiety. Now he has to relax again and when he is relaxed he is asked to stop imagining. These steps then start all over again. Every time that the stimuli is not strong enough anymore, he is asked to think of something more anxiety producing. Belkin described this in the following order [belkin 88]:
relax, imagine, relax, stop, imagine, relax, stop ...

Graded exposure

Graded exposure works almost the same as systematic desensitization, but now there is no longer the relaxation part. Instead of having the subject imagine the anxiety producing stimuli, he is now exposed to the real anxiety producing stimuli, in vivo [jansson 86], [james 83]. For instance, a person afraid of spiders can be treated by having the person watch a photo of a spider. When he is used to this, he can be shown a spider from a distance. After this the subject can be taken to the spider and eventually be asked to touch the spider. This simple sequence can take several sessions to complete!

Flooding and implosion

With both these treatments, the subject is immediately exposed to the highest level of anxiety producing stimuli. Unlike with graded exposure and systematic desensitization, the subject is no longer exposed step by step. This is like throwing someone in the swimming pool and not having him step down a ladder. Implosion uses imaginal stimuli and flooding uses in vivo.

Participant modelling

With participant modelling, the subject learns to overcome his anxiety by following a fearless model. This can be the psychologist. When the subject sees that the model has no problem exposing himself to the stimuli, he might start to copy the models behavior. For instance, when the subject is afraid of spiders and sees the psychologist touch the spider, the subject might want to believe it is not as dangerous as he thought.

Assertiveness and social skill training

Especially with social phobias, the subject has a lack of confidence in himself. This can be trained with assertiveness and social skill training. This teaches people how to respond in a social situation and how to express their opinions in a normal way. Techniques used are: role playing, desensitization, and positive reinforcement.

Aversion therapy / positive reinforcement

The final treatment described here is a form of behavior modification through rewards or punishment. The punishment can be used to prevent a subject from certain behavior. For instance, giving disulfiram to an alcoholic will cause severe psychological consequences when drinking. Positive reinforcement was used in a hospital ward where mental patients could earn tokens as a reward for performing a desired behavior. These tokens could then be used to buy privileges or luxury items.

Choosing a treatment

The treatment used was chosen from the treatments described in the section about behavioral therapy. Virtual Reality has the advantage that the environment that the user sees can be controlled with high precision. Using this higher control, it is hoped to get a better understanding about presence, and to have a better treatment available. Because of this reason, flooding and implosion are discarded, since these treatments depend on showing the subject immediately the highest level of anxiety inducing stimuli. To make sure that it is the Virtual Reality that helps the subject and not the relaxation, systematic desensitization is discarded. Aversion therapy and positive reinforcement are discarded because they work with physical rewards or punishments. Participant modelling is hard to do in Virtual Reality because it requires two people to be present in the same environment.

Using this knowledge, it was decided that the treatment given would be a form of graded exposure, but using computer generated images instead of imaginal or in vivo. The term used for this is going to be Virtual Reality Graded Exposure.

Development of environments

To give the user the feeling of height, it was decided to make models of places that already give people a sensation of height. Different scenarios that came up to be built were: To be able to treat the subjects, as many of these scenarios as possible had to be implemented. The problem of implementing these scenarios is that nobody has built something before that had to do with heights. Looking at the literature gave some clues about presence, but there were no clues what gave height sensation. Talking to the psychologists did not help either. To overcome this problem, it was decided to build a prototype of a height environment during the summer. The prototype would be tested on people that came to the GVU center for a demo in VR.

Once a month, the GVU center has an afternoon where the center is open to all visitors. People working in the GVU center demonstrate their work and answer questions. Using the people that come to these so called demo days, we tested the applications, and asked them what could be improved. Using this technique, we hoped to overcome some of the problems of prototyping [sol 92]: not enough validating of the application, and accepting the prototype too quick as a finished model. At the end of the summer, all the work that had been done during the summer had to be evaluated, to learn what caused the height sensations and to use this knowledge from the first environment to build the rest.

Since the hardest part of building applications for VR is creating the models and not building the software, it was decided to keep the prototype as an environment that could be used in the experiment. To prevent us from just building the software and the models without thinking first what they should look like, it was decided to build the first environment using the layered approach of Foley [foley 90]. This approach enabled us to get some idea about the application itself, before building it.

Finally, we needed to select one of the environments to be built as a first prototype. The application should also be used during the summer as a demonstration. To give the people coming over for a demo as much interaction as possible, we wanted to build an environment with which they could interact. This essentially eliminated all the environments except the elevator. The user should be allowed to control the elevator.


This section will give some of the requirements put on the environments. Some of the requirements were already given in the previous section and some of them were given by the people in charge of the project. The final chapter will check to see if these requirements have been met and, if they were not met, what went wrong. The following chapter will describe the steps taken building the first environment, and the lessons learned from building this environment. The other environments were then built using the knowledge from the first environment, the elevator.

Choosing a phobia Designing environments TOC
Rob Kooper

Last modified: Wed Aug 9 12:19:10 GMT 1995