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Effect of Self-Avatars on Performance in Virtual Environments
- 1. Effect of Self-animated Avatar in Virtual Environments Mukund Raj 1
- 4. Presentation Outline 1. Introduction – Motivation – Research Problem – Why is this important? 2. Background and Hypothesis – Avatars – Embodiment – Interface – Hypothesis 3. Experiment 1 – Pilot Study – Introduction – Description – Results and Conclusion 4. Experiment 2 – Follow up Study – Introduction – Description – Results and Conclusion 5. Final Discussion – Conclusion – Future Work
- 7. • Perception and action
- 8. Avatars • Self Avatars, technology • Earlier Avatar Studies
- 9. Motivation • Gesture recognition – Kinect – Leap – Smartphones with gyroscopes • Modern Graphic Cards • Web based 3D graphics APIs 9 • Animated self-avatar based interfaces
- 10. Problem • What is the effect of presence of a self animated avatar on user performance in a virtual environments ? – Is there an effect? – Does the strength of the effect depend upon level of immersion? 10
- 11. Why is this important?
- 12. Presentation Outline 1. Introduction – Motivation – Research Problem – Why is this important? 2. Background and Hypothesis – Avatars – Embodiment – Interface – Hypothesis 3. Experiment 1 – Pilot Study – Introduction – Description – Results and Conclusion 4. Experiment 2 – Follow up Study – Introduction – Description – Results and Conclusion 5. Final Discussion – Conclusion – Future Work
- 13. Background • Mohler et. al. The Effect of Viewing a Self-Avatar on distance Judgments in an HMD-Based Virtual Environment • Kadri et.al. The Influence of Visual Appearance of User’s Avatar on the Manipulation of Objects in Virtual Environments • ViewCube: A 3D Orientation Indicator and Controller • Ziemek, et.al. Evaluating the effectiveness of orientation indicators with an awareness of individual differences. 13
- 14. Kadri et.al. The Influence of Visual Appearance of User’s Avatar on the Manipulation of Objects in Virtual Environments 14
- 15. Background - Embodiment • Embodied Cognition – Role of the body in cognition • Sanchez-Vives : Virtual Hand Illusion Induced by Visuomotor Correlations • Margaret Wilson, Six Views of Embodied Cognition – Cognitive work can be offloaded onto the real world 15
- 16. Background - Interface • Lok et.al. Effects of Handling Real Objects and Self-Avatar Fidelity on Cognitive Task Performance and Sense of Presence in Virtual Environments • Ban et. al. : Magic Pot: Interactive Metamorphosis of the Perceived Shape – Pseudo haptics • Robert J.K. Jacob, Linda E. Sibert, Daniel C. McFarlane, M. Preston Mullen, Jr. Integrality and Separability of Input Devices 16
- 17. Effect of Self-Avatars • Familiar Auxiliary orientation indicator during manipulation. • Better sense of presence and embodiment in virtual environment. – Due to synchronicity between visual and proprioceptive cues. • More natural interface closer to real world performance. 17
- 18. Hypothesis • Presence of animated self-avatar will result in improved performance in an orientation matching task. • The strength of the effect will be stronger with higher immersion. 18
- 19. Plan of Work • Pilot Study – Kinect Based 3D Object Manipulation on a Desktop Display. SAP 2012. • Main Experiment – An improved version of the pilot. – Two immersiveness conditions, two visual feedback conditions in each 19
- 20. Presentation Outline 1. Introduction – Motivation – Research Problem – Why is this important? 2. Background and Hypothesis – Avatars – Embodiment – Interface – Hypothesis 3. Experiment 1 – Pilot Study – Introduction – Description – Results and Conclusion 4. Experiment 2 – Follow up Study – Introduction – Description – Results and Conclusion 5. Final Discussion – Conclusion – Future Work
- 21. Pilot Experiment • Task – Object rotation to match orientation using two modes ‘swipe’ and ‘twist’. • Display Conditions – Self avatar present vs sphere present • Performance measure – Time to completion • Individual difference factors – Gaming experience & Gender (correlated) 21
- 22. Introduction • Controlled experimental evaluation of a Kinect based user interface. • 3D object manipulation in virtual environment. • Two variations - with & without self avatars.
- 23. Questions • Does self avatar have observable effect on interfaces for object manipulation in virtual environments on a desktop display? • Are there strong individual differences in the effect? – Make interface more accessible
- 25. Experimental task • Orientation matching 3D object by rotating object in virtual world.
- 26. Interface - Display Conditions • Sphere Condition • Self Avatar Condition * Between subjects design used
- 27. Interface – Interaction Methods • Swipe – Rotation along direction of hand translation • Twist – Rotation about the wrist
- 28. Experimental objects • Objects Number of objects Trials per object Training 1 6 Test 12 1 Training Object Test Object #1
- 29. Experiment Setup • Kinect • Orientation Sensor • Wireless Mouse
- 30. Analysis
- 31. Result – Completion Time • No significant difference between sphere and avatar condition overall
- 32. Result – Completion Time • Difference as function of gender and video game experience.
- 33. Gaming experience / Gender ?
- 34. Results – Manipulation modes • Difference in manipulation mode as a function of gender/gaming experience
- 35. Pilot study conclusion • Effect of self avatar on performance of only a subset of users – Necessary to check for individual differences in performance data
- 36. Presentation Outline 1. Introduction – Motivation – Research Problem – Why is this important? 2. Background and Hypothesis – Avatars – Embodiment – Interface – Hypothesis 3. Experiment 1 – Pilot Study – Introduction – Description – Results and Conclusion 4. Experiment 2 – Follow up Study – Introduction – Description – Results and Conclusion 5. Final Discussion – Conclusion – Future Work
- 37. Key Learning • There is an effect of self avatar display condition. • Need to look closer at individual differences • Missing – Effect of immersiveness – Uncorrelated individual difference factors – Did not look if task difficulty interacts with display condition 37
- 38. Main Experiment • Intro • Description
- 39. Main Experiment • Orientation matching task – refined interface • Participants – 16 subjects per condition X 4 = 64 total subjects – Controlled for spatial cognitive ability (tested) 39
- 41. Procedure • Task – Object orientation matching – 15 objects per user trial • User Interface – Swipe mode – Twist mode - Modified with restriction on wrist rotation – Automatic mode switching – Automatic match detection – Maximum time limit 41
- 42. Design • Two Immersiveness conditions (Between Subjects) – High immersiveness - With stereo mode enabled – Low immersiveness - Without stereo • Two visual feedback conditions (Between Subjects) – With self Avatar – Without self Avatar • Axis of rotation and amount of rotation chosen from a uniform distribution (Fixed for all trials once selected) 42
- 43. Axis selection
- 44. Interface - Display Conditions • Sphere Condition • Self Avatar Condition * Between subjects design used
- 45. Interface – Interaction Methods • Swipe – Rotation along direction of hand translation • Twist – Rotation about the wrist
- 46. Experimental objects • Objects Number of objects Trials per object Training 1 6 Test 12 1 Training Object Test Object #1
- 47. Experiment Setup • Kinect • Orientation Sensor • Wireless Mouse
- 48. Analysis • One Way ANOVA – average time as dependent variable and visual display as independent variable • 2 (visual display) x 2 (stereo condition) ANOVA • ANCOVA with spatial abilities as covariates • 2 (visual display) x 2 (task difficulty) ANOVA 48
- 50. Result – No significance
- 52. Anticipated Contribution • Answer to the question whether self-avatars in a virtual world any effect. • Does the strength vary with level of immersion or – Individual difference – Task difficulty • Designing new virtual worlds with avatars and designing interfaces in virtual environments 52
- 53. Presentation Outline 1. Introduction – Motivation – Research Problem – Why is this important? 2. Background and Hypothesis – Avatars – Embodiment – Interface – Hypothesis 3. Experiment 1 – Pilot Study – Introduction – Description – Results and Conclusion 4. Experiment 2 – Follow up Study – Introduction – Description – Results and Conclusion 5. Final Discussion – Conclusion – Future Work
- 54. Discussion
- 55. Final Conclusion
- 56. Possible Extensions • Study the effect in an HMD based virtual environments. • Effect on translation tasks. • Effect on tasks involving translation and rotation. • Effect on size perception. 56
- 57. Future Research • Different controller object in hand • Automatic twist/swipe mode detection • Replace orientation sensor with a low cost mobile device accelerometer • 6DOF task • Stereographic displays • Symmetrical objects • Tactile Feedback • Comprehension vs. Manipulation
Editor's Notes
- Evaluation of effects (due to various causes) in a task. Mention avatar = self animated avatar now. Tried to explain the question that I will try to answer, the problem that’s expected, the idea that would get the solution, experiments actually do it. Along the way I’ll mention results from research papers that I think are relevant.
- When the time comes that we come
- Tie self avatar with earlier talk. What are avatars? Avatars are the digital representation of humans online, or as in our context, in virtual Environments. Self-avatars, the first-person representations of the users Themselves. Earlier avatar studies have shown inconclusive results on spatial cognition tasks. <break> 2. Self avatar is used in a variety of viewpoints and our interface renders an animated representation of the user’s arm and hand. Previously using avatars needed expensive motion capture equipment, but now we have the technology to build interfaces using avatars at a much lower cost. That brings up the question whether there are benefits of having such a self avatar extending into the virtual world. Could they help in offloading of cognitive work or provide a frame of reference? Could they help the user perform better just by making the interface more natural?
- The reason why perception in action is especially interesting now is because… **I’d like to start with the motivation behind this research… we are seeing a lot of devices that can be used for gesture recognition coming out at commodity prices These hardware when combined with power of … Not only An ability to build and make available easily a new kind of interface. That is all the technology we need to build Easy to build at a low cost. Also easy to make it widely available. This has become possible only recently, hence not much work is done to understand how the presence of self avatars effect the user’s actions in a virtual world.
- The effect here is measures by keeping track of time to perform a task by the users in the virtual environment.
- In an earlier study here, Mohler…. Mohler – There is an effect of avatars on distance perception. Kadri – Arrow avatars influence the way user manipulate objects. The cues have an effect, the question is can those effects translate into improvement in performance? Khan’s & Tina’s don’t use avatars but does find an effect of having orientation indicators and that they help in object manipulation. The ideas is that if the hand can also act as a familiar orientation indicator. Tina’s paper in addition talks about individual differences – how different people may be help differently by the presence of the orientation indicator. -- Orientation indicator ?
- According to the theory of embodied cognition, body plays a role in cognition (what role?) In the virtual world is could be possible that the avatar may take the role of the body for purposes of cognition. Sanchez-Vives -illusions of ownership and proprioceptive displacement could be induced with only visuomotor stimulation, specifically, the lesson here is that embodiment is possible even thought the avatar is located in front of the user and is not colocated as long as we have a high fidelity representation of the user actions in the form of an avatar. In margret wilsons study six views of embodied cognition, it is suggested that cognitive work can be offloaded to environment. Here again the avatar may facilitate this offloading by providing the user with a familiar orientation indicator for object manipulation. Here we see that avatars, essentially, help make the interface with virtual world closer to object manipulation in the real world. Environment is part of the cognitive system???
- And since we want to make the interface as close to interacting with real world objects as possible, the last set of important background work deals with interfaces. Lok - Manipulating a real object in hand brings performance closer to that of manipulating the object in the real world. Magic pot – we see that the shape of the object in real hand need not have the exact shape of the virtual object being manipulated for perceiving the shape of the object shape on the VE. Integrality – The task and the interface are both integral in nature. Match control structure of interface with perceptual structure of the task. All these results are important to the final interface using self avatars.
- Summing up its possible that self avatars may provide users with a familiar auxiliary orientation indicator How each of these may in turn affect performance? Embodiment and presence?
- The expectation is that all these effects would translate into improved performance and so the hypothesis is that… Point 2 – especially since a higher immersion could lead to better sense of presence and embodiment.
- In order to go about conducting the study, the plan of work involves two experiments- Pilot study – to test the feasibility of the building a self avatar based object manipulation interface and running user experiments on it. Main experiment – uses lessons learnt from the pilot study.
- I would like to start off with a quick , overview of the paper.. 1. We have conducted a controlled… 2. The interface itself is a ,Gesture based interface, for manipulating 3D objects in virtual world using the kinect sensor, . 3. We compared two variations of the interface, one of which used self avatar and the other that did not. Why did we do this?
- More concretely,… 1….. Does self avatar have observable effect on interfaces for object manipulation in virtual worlds on a desktop display? Intuitively having a self avatar does look like a more natural way of interaction, but we wanted to see if it translated into measureable effect in performance on a desktop display??? <break> 2. Also, in the real world it is also important to ask - are there strong individual differences in the effect? In other words, does performance of user groups vary significantly when using the interface? This becomes especially important when we are looking to make the interface accessible to the largest possible user group.
- To evaluate the interface, we chose the orientation matching task, mainly due to the ease of measuring performance in it and also as the task is known to be non trivial for larger rotations. As seen in the picture here, the screen is split into left and right regions. Objects at different orientations , appear in both regions, in each successive trial. The object on the right is then rotated by the user, to match the orientation of the object on the left.
- The interface has two variations based upon display conditions or what the users see as feedback for their arm motion The picture on the top shows the 1st variation – also called ‘Sphere condition’ in which a sphere of the size similar to that of the hand is rendered based upon the position of the right hand while interaction occurs. Only feedback to the user in this condition is a sense of position of the hand. Also, in the Sphere condition, the frame of reference is unclear. The picture below shows the other variation – also called the self avatar condition in which motion of shoulder, elbow and wrist are accurately mapped onto the avatar. Fingers, however, are not animated. Self avatars can provide the user with an egocentric and anthropomorphic frame of reference as well as a more natural interface ----- We used a between subjects design for assigning participants to the feedback conditions. ** Also, Male and female participants were evenly distributed for the sphere and the self avatar conditions. ----
- The interface provides two modes of rotation to change the orientation of the objects. First is Rotation along hand motion also referred to as swipe mode. [VIDEO] As you can see, the user rotates the object along an axis on the plane of the display and perpendicular to the direction of hand motion. This is similar to rotating objects using the virtual sphere method, except that we use hand gestures instead of moving the mouse pointer. The second method of interaction is rotating the object about the axis of their wrist also referred to as twist mode. [VIDEO] This is closer to how we manipulate objects in the real world. Here the user can rotate the object about any axis just by aligning their wrist with that axis and performing a twist gesture. ** Both interaction methods were enabled in each of the display conditions and the user could select either mode at any time during a trial. ** For larger rotations users were able to employ ratcheting and accomplish larger rotations as sum of smaller rotations. ** Also as seen in the video, color of the object changed when the avatar’s hand came close to the object to incorporate a sense of contact. Users were only able to manipulate when the avatar hand was close to the object .
- The user had a chance to practice with a training object before the recorded trials. Each participant gets 6 trials to practice with a single practice object, which is the one shown on the picture on the left after which they were ask to perform the task on 12 distinct trial objects, one of which is shown in the right figure. ---------- ***** Completion time and number of times each mode of rotation was used were recorded for each trial for all participants. ******** ----------
- In the experimental setup, We used the Kinect for recovering joint orientations of the user for animating the avatar. In addition to the Kinect we also used an orientation sensor strapped around the hand of the user for improving the accuracy of the wrist orientation. And, a wireless mouse used by the user to indicate the mode of rotation for each gesture - whether along the hand motion/ or about the wrist axis. ----- ** Geometric and display field of views were matched to improve realism and sense of embodiment of the avatar. ///////////////////////And Gender and gaming experience were also recorded in order to check for “individual differences”.
- We looked at the time taken by each participant to complete all 12 trials. Here we have plotted the average completion time for the two display conditions. The first and second bar show the average completion time for the self avatar and sphere display conditions respectively. And, we can see that, there was no significant difference in performance between sphere and avatar conditions overall
- However.. There was difference in performance in visual display condition as function of gender and video game experience. On the graph we again have average completion time for each condition, now split by gender. It can be seen that although everyone performed similarly in the self avatar condition, female participants took noticeably longer to complete the trials in the sphere condition. ---------------split----------------- It is important to note that , Gaming experience and gender in our participant pool were highly overlapping and we cannot associate the effect to either gaming experience or gender alone from the available data. Here we see an effect of “individual differences” in our interface where the display condition had an effect on performance of a subset of participants.
- As seen in the earlier graph, and more clearly in here, gender and gaming experience gender and gaming experience significantly overlapped in our participant pool. It would be interesting to see the performance of female gamers and male non – gamers using this interface. Generic test. Spatial abilities correlation
- We also recorded the mode of rotation indicating which mode the participants used whether along the hand motion or about the wrist axis and again we see an effect of “individual differences”. Male/Gamer participants used both modes almost equally while female/non gamers participants relied more on rotation along the hand motion. Ideally a good sense of object orientation in virtual world would afford a predisposition toward rotation about wrist axis as it would be more efficient if used correctly. Also it is closer to the natural way of manipulating objects in the real world and object can be matched to the target orientation in a single motion if the appropriate axis needed is known as it supports rotation along the line of sight as well.
- We compared user performance in two variations of a gesture based interface for object manipulation interface in virtual world . 1. We found that there was an.. “Effect of self avatar on performance of only a subset of users” 2. Hence we see when evaluating such interfaces, “Necessary to check for individual differences in performance data” Latest tracking devices such as the Kinect and leap, open up new ways of interacting with the virtual world. We did a controlled study of one such possibility and we saw one variation of the interface showing significant effect of individual differences while the other did not. The key message here is that in evaluating performance of such interfaces its important to keep a look out for individual differences, which can be significant , to really understand the strength and weaknesses of the system. ------------ Presence of self animated avatar showed effect in performance of only a subset of users. Male Gamer users did not show significant effect Non gamer female users had an effect between the conditions
- We also did not test for immersiveness, could it be that the running on the desktop caused the effect not to show up in all individuals? Weak effect due to running on a desktop.
- Keeping in mind the goal of the research… and also lessons learnt from the earlier experiment the new experiment is designed. Interface made more intuitive and easier for the users to use. Instead of just asking gaming experience, also give them a test.
- The task will be to match the orientation of 15 distinct objects appearing in pairs at different orientations. The axis and the amount of rotation to match the object is selected from a uniform distribution as mentioned.
- The interface has two variations based upon display conditions or what the users see as feedback for their arm motion The picture on the top shows the 1st variation – also called ‘Sphere condition’ in which a sphere of the size similar to that of the hand is rendered based upon the position of the right hand while interaction occurs. Only feedback to the user in this condition is a sense of position of the hand. Also, in the Sphere condition, the frame of reference is unclear. The picture below shows the other variation – also called the self avatar condition in which motion of shoulder, elbow and wrist are accurately mapped onto the avatar. Fingers, however, are not animated. Self avatars can provide the user with an egocentric and anthropomorphic frame of reference as well as a more natural interface ----- We used a between subjects design for assigning participants to the feedback conditions. ** Also, Male and female participants were evenly distributed for the sphere and the self avatar conditions. ----
- The interface provides two modes of rotation to change the orientation of the objects. First is Rotation along hand motion also referred to as swipe mode. [VIDEO] As you can see, the user rotates the object along an axis on the plane of the display and perpendicular to the direction of hand motion. This is similar to rotating objects using the virtual sphere method, except that we use hand gestures instead of moving the mouse pointer. The second method of interaction is rotating the object about the axis of their wrist also referred to as twist mode. [VIDEO] This is closer to how we manipulate objects in the real world. Here the user can rotate the object about any axis just by aligning their wrist with that axis and performing a twist gesture. ** Both interaction methods were enabled in each of the display conditions and the user could select either mode at any time during a trial. ** For larger rotations users were able to employ ratcheting and accomplish larger rotations as sum of smaller rotations. ** Also as seen in the video, color of the object changed when the avatar’s hand came close to the object to incorporate a sense of contact. Users were only able to manipulate when the avatar hand was close to the object .
- The user had a chance to practice with a training object before the recorded trials. Each participant gets 6 trials to practice with a single practice object, which is the one shown on the picture on the left after which they were ask to perform the task on 12 distinct trial objects, one of which is shown in the right figure. ---------- ***** Completion time and number of times each mode of rotation was used were recorded for each trial for all participants. ******** ----------
- In the experimental setup, We used the Kinect for recovering joint orientations of the user for animating the avatar. In addition to the Kinect we also used an orientation sensor strapped around the hand of the user for improving the accuracy of the wrist orientation. And, a wireless mouse used by the user to indicate the mode of rotation for each gesture - whether along the hand motion/ or about the wrist axis. ----- ** Geometric and display field of views were matched to improve realism and sense of embodiment of the avatar. ///////////////////////And Gender and gaming experience were also recorded in order to check for “individual differences”.
- To analyze the data, I plan to use one way anova with time as dependedt and visual display as an independent variable to look if there is an effect of display condition overall. The a multifactor anova with 2 visual display conditions and 2 stereo conditions to see if there is an effect of visual display as a function of immersiveness condition. Lastly ancova- with spatial abilities as covariates…used to determine whether individual differences factors account for the visual feedback condition effects.
- backed by results from controlled experiments
- Interesting ideas to explore further.
- Questions – 1.Visually faithful avatar benefits? 2. Papers that embodiment improve task performance 3. Get paper for immersiveness is better. Future – Now there is a way to evaluate interfaces. Predict the performance on another task On HMD? Immersive environment. Haptics & Mobile Haptic Interfaces for Embodiment in Virtual Environments Movement, Action, and Situation: Presence in Virtual Environments – How well the overall situation in the VE meshes with the actions afforded in the VE effect of sense of embodiment Relation beteween immersion and embodiment? That high immersion leads to higher embodiment. Sanchez paper?