For most people, the term Virtual Reality will bring to mind visions of imaginary worlds, complicated devices and gaming teens, but nowadays, VR is increasingly being used for purposes other than gaming. Surgeons, for example, use it to operate using a robot. It is also used in training and education in the military, sports, healthcare and engineering. These tasks benefit tremendously from VR, because the environment engages multiple senses and creates a feeling of being located in a virtual world. This feeling is called Presence.
We know certain things are disruptive to this sense of Presence – the equipment that is used for example: head mounted displays are often heavy, and sometimes glasses steam up or get smudges on them. Noises from the physical environment, or bumping into a table can disturb the feeling of Presence. These small disturbances can remind a user that he or she is using a VR system, and is not actually in the physical environment. Technical problems, such as sudden changes in frame rate or unresponsive controls, can also cause a person to lose the feeling of location in the virtual world.
To date, very little research has focused on what happens to people when unrealistic events occur in virtual reality, such as strange social responses from avatars or skies that change color too rapidly. The effects of these kind of events are sometimes mentioned as a side note when discussing interviews with participants, but hardly receive any real attention.
The concept often applied to explain how people deal with unrealistic events in fiction is called ‘suspension of disbelief’. According to this concept, people choose not to pay attention to certain aspects of fiction that hinder their enjoyment of it: they simply ignore the fact that what they see is impossible. However, it seems unlikely that when unrealistic portrayals are encountered, they can be simply ignored. In my own study, I started out from the assumption discussed in literature that people have certain expectations about what is acceptable. When viewing science fiction movies, for instance, no one will be surprised to see an alien life form show up half way through, but if the main character suddenly starts to use magic this will grab the attention of the viewer and prompt him or her to question the likelihood of such an event happening within the setting of the story. But after expectations are revised by the viewer, he or she may accept the level of realism and continue watching, no longer paying attention to the addition of magic to the story world.
So if expectations have something to do with how acceptable a media portrayal is, what does this mean for VR and Presence? Sudden unrealistic portrayals (e.g., an alien suddenly appearing in an otherwise realistic telemedicine environment) could break the feeling of Presence once, but subsequent similar portrayals may not cause any interruption to Presence. This hypothesis was tested in my study. In my experiment, participants were guided through a virtual house. One of the rooms they explored was flipped upside down, so that the furniture was on the ceiling.
Most of the participants had a strong reaction the first time they entered the room and noticed it was upside down. Many asked for confirmation (“Is this room upside down?”), and spent some time viewing the room. But when returning to the room later on, they not only spent less time there, often just glancing at it, or ignoring it altogether. When asked what they thought of the house later, many responded with “this house is really realistic” and only mentioned that the upside down room was not realistic when they saw it again. The more participants experienced the environment as realistic, the more they also felt present in the house. Most importantly, participants indicated that while they felt less present the first the time they visited the upside down room than they did on average, these breaks in presence did not occur the second or third time they entered the room.
This knowledge can help with the design of virtual environments. It means the use of VR does not have to be limited to realistic portrayals, but also that it is not essential for all aspects of a VR to be perfectly realistic.
Paula den Ouden