Week 10 Summaries
Variations in Physiological Responses of Participants During Different Stages of an Immersive Virtual Environment Experiment
The authors intend to analyze the various levels of immersion a participant goes through during an immersive virtual experience. To analyze the subjects, they use electro-dermal activity (EDA), Heart Rate (HR) and Heart Rate Variability (HRV) as measures. They also analyze the impact of the quality and realism of textures of the world on the experience. The virtual environment was created with the help of a CAVE-like setup. The experiment consisted of 4 stages: An activity-less state in a dark room, an introductory training environment and the final two stages in the actual virtual world.
The authors found that the participants feel stressed when they are introduced to a new environment and the stress levels decrease as they become more accustomed to it but then increases which may be due to them getting used to the environment and thus being able to find flaws in the world. They also felt more stressed when the frame rate was changed or texture quality was modified. But more non-repetitive textures resulted in a more realistic world and experience.
The Uncanny Valley: Effect of Realism on the Impression of Artificial Human Faces
The Uncanny Valley refers to the dip in the graph showing how real a thing is and how it is perceived, where when something looks almost real but has some minor uncanny difference then that breaks the whole experience. This paper tries to quantify its existence and what are the factors that may be causing it. The study involves participants looking at a low resolution and quality face which was gradually morphed the various features into a more real face while changing the order. The participants then had to rate the image on a numerical scale from pleasant to unpleasant. The terms “pleasant” and “unpleasant” themselves are a part of a deeper thought and analysis.
In the first experiment, there was an unrealistic image and this led to no Uncanny Valley. The second one consisted of gradually growing eyes followed by the head. People felt uncomfortable midway through the morphing. In the 3rd round, the abnormal eyes on a real face led to a very unpleasant experience for the people and the 4th experiment confirmed this. The conclusion was that there might not be an Uncanny Valley as such but people are highly attuned to features of a face and especially the eyes.
This was an interesting study in my opinion because the Uncanny Valley in itself is an intriguing phenomenon but the fact that people notice specific features instead of the “any uncanny” difference.
Physiological Measures of Presence in Stressful Virtual Environment
The authors set out to test the possibility of using physiological and other biological measures as a way to gauge the “presence” a person felt. Their hypothesis was that if the person showed the same physiological reactions as in the real world then they felt that they were present in the virtual world. They monitored the heartbeat, skin conductance and temperature of the subjects to determine this. The participants were trained first so as to acquaint them to the virtual world and not show any stress because of the new environment. In the other room, there was a pit, which consisted of a 20-ft deep unguarded fall. The subjects are asked to go around the room and drop balls at certain spots in the pit. The experiment varied with the help of certain parameters like the frame-rate and time the subjects were exposed to the VE. Lowering the frame-rate had a negative impact on the experience. Multiple exposures to the same virtual environment also decreased the presence. Passive haptics on the other hand greatly increase the presence. In general they found that heart-beat gave them the most consistent and clear results followed by skin conductance.
I can see what the authors mean by exposing people to real-world scenarios in a virtual world and checking for physiological reactions to measure presence. And it seems to work to a large extent but are these not already documented with the Vietnam study etc.?
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