Sally Linkenauger

Alumni of the Department Human Perception, Cognition and Action
Alumni of the Group Perception and Action in Virtual Environments

Main Focus

I am a post doctoral fellow in the here at the Max Planck Institute for Biological Cybernetics in the Human Perception, Cognition, and Action group. Specifically, I study the influence of the body on the scaling of perceived extents. I using virtual reality and stereodisplays to manipulate the body and its ability to interact with the virtual environment to access how this may influence perceived sizes and distance.

The influence of a Virtual Body on Size and Distance Perception in Virtual Environments

S.A. Linkenauger, B.J. Mohler, & H.H. Bülthoff

Introduction

It has been suggested that in order to perceive sizes and distances angular information needs to be rescaled to a metric appropriate for space perception [1]. Previous research has suggested that the body is the used metric for scaling estimates of spatial layout [1]. Unfortunately, this assertion is difficult to test, because in real environments, the body is difficult to manipulate in a controlled and specific fashion. However, individuals can experience virtual environments (VEs) in which they have a virtual body that is presented in first person perspective and animated in real time. Further, in VEs, we can precisely manipulate specific aspects of the self-representing avatar, and resultantly, we can test whether aspects of the sensory experience of the body influences the perception of space.

Goal

Our research aim is to assess whether individuals use their self-representing avatars body to scale perceived sizes and distances in VEs.

Method

We have run several experiments in VEs to investigate the effects of a virtual avatar body on size and distance perception (see Figure). Participants viewed the VE in a stereoscopic, head-mounted display (HMD). Participants head and hand movements were tracked in real time and a camera and virtual hand were animated in the VE. We increased or decreased the size of the self-representing avatars hand and had participants verbally estimate the sizes of spheres in VEs. In another experiment, we increased or decreased the length of the self-representing avatars arm and had participants estimate the distances between themselves and reachable distances using a visual matching task.

Initial results

We found that participants estimated the sizes of the spheres to be smaller when their virtual hands were larger in comparison to when their virtual hands were smaller. We also found that participants estimated the reachable distances to be smaller when their virtual arm was longer than when their virtual arm was shorter.

Initial conclusions

These results support the notion that the body is used to scale perceived size and distance [1]. Future research will disentangle whether body size, i.e. arm length, or action capabilities, i.e. maximum reach, or both are responsible for the scaling of apparent sizes and distances. Similarly, we will investigate how this scaling occurs with other aspects of the body, such as leg length and foot size.

Left: Participant in experimental set-up; Center: View of participant in size perception study; Right: View of participant in distance perception study.

References

Proffitt DR and Linkenauger SA(2011) Perception viewed as a phenotypic expression, In: Tutorials In Action Science, (Ed) Prinz W, MIT Press, Cambridge, MA, USA
Linkenauger SA, Mohler BJ and Bülthoff HH (2011) Welcome to Wonderland: The Apparent Size of the Body Influences Perceived Extents in Virtual Environments, Journal of Vision (poster), 11(11:VSS 2011 Abstracts) 70.
Linkenauger SA, Mohler BJ and Bülthoff (2011): Welcome to wonderland: The apparent size of the self-avatar hands and arms influences perceived size and shape in virtual environments, Perception (Talk), 40(ECVP Abstract Supplement) 46.

Curriculum Vitae

Sally Ann Linkenauger

Max Planck Institute for Biological Cybernetics

Spemannstr. 38

Tuebingen, Germany 72012

EDUCATION

Max Planck Institute for Biological Cybernetics, Post-doctoral fellow: 2010-present.

University of Virginia, Charlottesville, Virginia: Ph.D. 2005-2010.

Masters Thesis: Handedness and reaching ability affect the perception of distance. November 2007

Dissertation: Sizing up the world: Body based perception and the perception of size.

August 2010

University of Virginia, Charlottesville, Virginia: B.A. in Psychology and Cognitive

Science, 2000-2004.

RESEARCH INTERESTS

Scaling of apparent extents, tool-use and motor simulation, sports performance and perception, handedness and body schema

FUNDING, FELLOWSHIPS, AND HONORS

Tandem Project for the Center for Integrative Neuroscience, Co-principle investigator, 2011, 2 years

Alexander von Humboldt Fellowship for Post-Doctoral Researchers, 2011, 2 years

ZiF Conference on Perception and Action Fellow, 2010

Distinguished Teaching Fellowship, 2009

PUBLICATIONS AND PRECEEDINGS

Peer Reviewed Manuscripts

Linkenauger, S., Lerner, M.D., Ramenzoni, V., Proffitt, D. (in press). A perceptual-motor deficit predicts social and communicative impairments in individuals with autism spectrum disorders. Autism Research.

^*Graydon, M., Linkenauger, S.A., Teachman, B. & Proffitt, D.R. (in press). Scared stiff: The influence of anxiety on action capabilities. Cognition and Emotion.

Witt, J.K., Linkenauger, S.A. & Proffitt, D.R. (in press). Get me out of this slump!

Visual illusions influence sports performance. Psychological Science.

^*Lee, C.L, Linkenauger, S.A., Bakdash, J. Z., Joy-Gaba, J.A., & Proffitt, D.R.

(in press). Putting like a pro: The role of positive contagion in golf. PLoS One.

Linkenauger, S. A., Mohler, B.J. & Proffitt, D.R. (in press). Body-based

perceptual rescaling revealed through the size weight illusion. Perception.

Leyrer, M., Linkenauger, S.A., Bülthoff, H.H., Kloos, U., & Mohler, B.J.(2011).The

influence of eye height and avatars on egocentric distance estimates in virtual environments, 8^th Symposium on Applied Perception in Graphics and Visualization (APVG 2011), ACM Press, New York, NY.

Proffitt, D.R. & Linkenauger, S.A. (in press). Perception viewed as a phenotypic

expression. In Tutorials in Action Science (Ed) W. Prinz, MIT Press, Cambridge, MA.

Linkenauger, S.A., Witt, J.K. & Proffitt, D.R. (2011). Taking a Hands-On Approach:Apparent Grasping Ability Scales the Perception of Object Size. Journal of Experimental Psychology: Human Perception and Performance.[Epub Ahead].

Linkenauger, S.A., Ramenzoni, V.C., & Proffitt, D.R. (2010). Illusory shrinkage and

growth: Body-based rescaling affects the perception of size. Psychological Science, 21.

Witt, J. K., Kemmerer, D., Linkenauger, S. A., & Culham, J. (2010). A functional role

for motor simulation in naming tools. Psychological Science,21.

Landy, D. & Linkenauger, S. (2010). Arithmetic Notation...Now in 3D! The 32nd

Annual Conference of the Cognitive Science Society, Portland, Oregon.

Linkenauger, S.A., Witt, J.K, Bakdash, J.Z., Stefanucci, J.K, & Proffitt, D.R. (2009).

Asymmetrical Body Perception: A Possible Role for Neural Body Representations. Psychological Science, 20.

Linkenauger, S.A., Witt, J.K, Stefanucci, J.K, Bakdash, J.Z. & Proffitt, D.R. (2009).

The effects of handedness and reachability on perceived distance. Journal of Experimental Psychology: Human Perception and Performance, 35.

^*Lessard, D. A., Linkenauger, S.A., & Proffitt, D.R. (2009). Look before you leap:

Jumping ability affects distance perception. Perception, 38.

Witt, J.K., Linkenauger, S.A., Bakdash, J.Z., & Proffitt, D. R. (2008).

Putting to a larger hole: golf performance relates to perceived size. Psychonomic Bulletin & Review, 15.

Bakdash, J.Z., Linkenauger, S.A., & Proffitt, D.R. (2008). Comparing decision-

making vs. control for learning a virtual environment: Backseat drivers learn where they are going. In Human Factors and Ergonomics Society 2008 Conference Proceedings

Witt, J.K., Linkenauger, S.A., Bakdash, J.Z, Augustyn, J.A., Cook, A., & Proffitt, D.R.

(2008). The long road of pain: Chronic pain increases perceived distance. Experimental Brain Research, 192.

^*Indicates undergraduate student whom Sally Linkenauger advised on the research and manuscript

Manuscripts Under Review

*Clarke, E., Linkenauger, S.A., Parasuraman, R., Greenwood, P.M. & Proffitt, D.R.

(under review). Ability modulates distance and slant perception in aquatic environments.

Manuscripts in Preparation

Linkenauger, S.A., Mohler, B.J. & Bülthoff, H.H. (in preparation). Welcome to

wonderland: The Influence of the Size and Shape of a Virtual Hand on the Perceived Size and Shape of Virtual Objects.

Linkenauger, S.A., Geuss, M., Mohler, B.J. & Stefanucci, J.K. (in preparation). The

Perception of the Hand is Less Susceptible to Optical Magnification: Evidence for a Perceptual Size Anchor in Near Space.

Linkenauger, S.A., Geuss, M., Mohler, B.J. & Stefanucci, J.K. (in preparation).

The perception of the hand is distorted when estimating object size.

Linkenauger, S. A., Zadra, J., Witt, J. K., and Proffitt, D. R. (in preparation). The effect

of effort to reach and grasp on the distance to targets in near space.

Linkenauger, S. A., Bakdash, J. Z., Stefanucci, J. K., Witt, J. K., and Proffitt, D. R. (in

preparation).Perceived distance influences imagined walking time.

Popular Press Coverage for Linkenauger, Witt, Bakdash, Stefanucci and Proffitt (2009)

Observations: A vast right-arm conspiracy: Study suggests handedness many affect body perception

APS Observer Magazine, Volume 22, Number 10, December 2009.

A vast right-arm conspiracy: Study suggests handedness many affect body perception (November 5, 2009),

Science Daily, EurekaAlert, PHYSORG.com, AllScienceNews.net!:

Southpaws have a different view (November 5, 2009)

Psych Central:

Popular Press Coverage for Witt, Linkenauger, Bakdash, and Proffitt (2008)

Hole in the head: Golf and perception (September 8, 2008), Interview,

ScienCentral:

Athletes in the zone may see the world differently (August 5, 2008), Technology & Science,

ABC News:

Do top athletes see the world differently? (July 9, 2008), Interview, The Bryant Park Project on National Public Radio:

Good golf players see the hole as larger than poor players (July 8, 2008), Science News, Science Daily:

The secret(s) to better golf (July 8, 2008), Editors Blog,

Golf Digest:

Study: Perception of hole size influenced by performance (July 7, 2008), Press release from Purdue University, mentioned in EurekaAlert!, e! Science News, and PHYSORG.com:

CONFERENCE PRESENTATIONS

Linkenauger, S.A. & Mohler, B.J. & Bülthoff, H.H. (2011). Welcome to Wonderland: The Apparent Size of the Self-Representing Avatars Hands and Arms Influences Perceived Size and Shape in Virtual Environments. Talk presented at the 34^th Annual meeting of the European Conference on Visual Perception, Toulouse, France.

Linkenauger, S.A. & Mohler, B.J. & Bülthoff, H.H. (2011). Welcome to Wonderland: The Apparent Size of the Self-Representing Avatars Hands and Arms Influences Perceived Size and Shape in Virtual Environments. Poster presented at the 10^th Annual meeting of the Vision Sciences Society, Tampa, FL.

Linkenauger, S.A. & Proffitt, D.R. (2008) The Effect of Intention and Bodily

Capabilities on the Perception of Size. Poster presented at the 8^th Annual meeting of the Vision Sciences Society, Tampa, FL.

Twedt, E. L., Linkenauger, S.A., Banton, T. , Proffitt, D. R (2008).The Effect of Biking

Effort on Perceived Distance and Slant. Poster presented at the 8^th Annual meeting of the Vision Sciences Society, Tampa, FL.

Bakdash, J. Z., Linkenauger, S.A., Stefanucci, J.K., Banton. T., & Proffitt, D. R. (2008)

Perceived Distance Influences Simulated Walking Time. Poster presented at the 8^th Annual meeting of the Vision Sciences Society, Tampa, FL.

Linkenauger, S. A. (March 2008).Graspability Influences Size Perception. Talk

presented at the University of Virginia Graduate Research Exhibition, Charlottesville, VA

Linkenauger, S.A., Witt, J.K., Bakdash, J.Z., and Proffitt, D.R.(2007) Handedness

effects body schema. Poster presented at the 7^th Annual meeting of the Vision Sciences Society, Sarasota, FL.

Witt, J.K., Linkenauger, S.A., Bakdash, J.Z., and Proffitt, D.R. (2007) Performance, not

ability, makes the golf hole look as big as a bucket. Poster presented 7^th Annual meeting of the Vision Sciences Society, Sarasota, FL.

Bakdash, J.Z., Linkenauger, S.A., and Proffitt, D.R. (2006) Separating the two Main

components of active navigation for learning a virtual environment: decision-making and control. Poster presented at the 7^th Annual meeting of the Vision Sciences Society, Sarasota, FL.

Linkenauger, S. A. (March 2007).The Effect of Handedness on Body Schema. Talk

presented at the University of Virginia Graduate Research Exhibition, Charlottesville, VA

Linkenauger, S. A. (March 2006).Orientation of Tools and Spatial Perception. Talk

presented at the University of Virginia Graduate Research Exhibition, Charlottesville, VA

Linkenauger, S., Witt, J., Stefanucci, J., & Proffitt, D. (2006). Ease to grasp an object

affects perceived distance. Poster presented 6^th Annual meeting of the Vision Sciences Society, Sarasota, FL.

Zadra, J. R., Linkenauger, S. A., & Proffitt, D. R. (2006). Effort affects perceived

distance to objects within reach. Poster presented 6^th Annual meeting of the Vision Sciences Society, Sarasota, FL.

TEACHING EXPERIENCE

Co-Instructor, Perception and Action: Philosophical Issues from Psychology to Neuroscience, Eberhart Karis University of Tübingen, Fall 2011

Instructor, The Structure, Function, and Evolution of Sensory Systems in the Animal Kingdom, University of Virginia, Summer 2010

Instructor, The Structure, Function, and Evolution of Sensory Systems in the Animal Kingdom, University of Virginia, Fall 2009

Instructor, Introduction to Perception Laboratory, University of Virginia, Fall 2008

Guest Lecturer (June 22, 2011). Eberhart Karis University of Tübingen Perception and Action- The Ecological Approach to Perception

Guest Lecturer (June 7, 2011). Eberhart Karis University of Tübingen Workshop on Rational Agency A Functional Approach to the Perception of Spatial Layout

Guest Lecturer (September 19, 2006)- University of Virginia- Introduction to Perception-

Visual Receptive Fields

Guest Lecturer (February 6, 2006)- University of Virginia- Introduction to Psychology-

Perception and Action

Teaching Assistant, Introduction to Perception, UVA Fall 2007

Teaching Assistant, Introduction to Psychology, UVA Spring 2007

Teaching Assistant, Introduction to Psychology, UVA Spring 2006

STUDENT SUPERVISION

Advisor for Masters Students

Markus Leyrer: M.A. Advisor: 2010, The effect of eye-height and avatars on egocentric distance perception in virtual environments (Co-advisor with Betty Mohler)

Nikola Bubalo: M.A. Advisor: 2011, Visual recalibration of gait following asymmetrical optic flow (Co-advisor with Betty Mohler)

Primary Advisor for Distinguished Majors Students (Senior Theses)

Meagan Graydon (2009-2010) Psychology undergraduate thesis: The role of anxiety in the perception of affordances Under review

David Lessard (2008-2009) Cognitive Science undergraduate thesis, awarded highest distinction: Look before you leap: The scaling of jumpable extents Published in Perception

John Rogers (2008-2009) Cognitive Science undergraduate thesis, awarded high distinction: Taking matters into your own hands: Effect of body scaling on the influence of a size contrast illusion

Charles Lee (2008-2009) Cognitive Science undergraduate thesis, awarded high distinction: Putting like a pro: the role of positive contagion in golf In press in PLoS One

Ellen Clarke (2007-2008), Psychology undergraduate thesis, awarded distinction: The effect of ability on slant perception in aquatic environments Under review

Melody Esmaldi (2007-2008). Psychology undergraduate thesis, awarded distinction: The effect of environmental context on the perception of near space

Noel Dereki (2006-2007), Cognitive Science undergraduate thesis, awarded highest distinction: The role of tools in automatic motor priming

PROFESSIONAL ACTIVITES

Ad hoc Reviewer

Journal of Experimental Psychology: General

Psychological Science

Society Memberships

Vision Sciences Society

American Psychological Society