12 research outputs found
Owning an overweight or underweight body: distinguishing the physical, experienced and virtual body
Our bodies are the most intimately familiar objects we encounter in our perceptual environment. Virtual reality provides a unique method to allow us to experience having a very different body from our own, thereby providing a valuable method to explore the plasticity of body representation. In this paper, we show that women can experience ownership over a whole virtual body that is considerably smaller or larger than their physical body. In order to gain a better understanding of the mechanisms underlying body ownership, we use an embodiment questionnaire, and introduce two new behavioral response measures: an affordance estimation task (indirect measure of body size) and a body size estimation task (direct measure of body size). Interestingly, after viewing the virtual body from first person perspective, both the affordance and the body size estimation tasks indicate a change in the perception of the size of the participant’s experienced body. The change is biased by the size of the virtual body (overweight or underweight). Another novel aspect of our study is that we distinguish between the physical, experienced and virtual bodies, by asking participants to provide affordance and body size estimations for each of the three bodies separately. This methodological point is important for virtual reality experiments investigating body ownership of a virtual body, because it offers a better understanding of which cues (e.g. visual, proprioceptive, memory, or a combination thereof) influence body perception, and whether the impact of these cues can vary between different setups
The Graph shows the self-reports of the participants about their ideal, current, lowest (since they were 18 years old) and highest weight (since they were 18 years old).
<p>These reports were collected from the EAT-26 and used to screen the participants for eating disorders, in addition to the written consent. Error bars represent one standard error of the mean.</p
The list of the items used for the questionnaire in the experiment and its scoring scale.
<p>The list of the items used for the questionnaire in the experiment and its scoring scale.</p
Graph showing the median score of the subjective self-reports organized into categories.
<p>Error bars represent 95% confidence intervals of the median.</p
Body size estimations: the participants were able to smoothly adjust the size of the avatar, ranging in width from (the underweight avatar) to (the overweight avatar).
<p>The pictures show the initial size of the PP avatar in each of the four trials.</p
Perspective of the participant during visual-tactile stimulation.
<p>The animated virtual hand reaches through the black curtain to stroke the left arm (A - overweight, B - underweight), the right arm (C - overweight, D - underweight), the left leg (E - overweight, F - underweight) and the right leg (G - overweight, H - underweight) of the body.</p
Affordance estimations: participants were able to smoothly adjust the width (from to ) of the gap between the poles.
<p>The pictures show the initial size of the gap in each of the four trials.</p
Plot of the ratio of the affordance estimates for the , and bodies.
<p>Error bars represent one standard error of the mean.</p
Plot of the ratio of the affordance estimations for the body before and after synchronous and asynchronous visual-tactile stimulation.
<p>Error bars represent one standard error of the mean.</p