Eye-Tracking in Practice: An Application to Human PosturesJürgen Symanzik — February 5, 2020...
Transcript of Eye-Tracking in Practice: An Application to Human PosturesJürgen Symanzik — February 5, 2020...
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Eye-Tracking in Practice:An Application to Human Postures
Jürgen Symanzik∗
withEric McKinney, Joanna Coltrin, Breanna Studenka
∗ProfessorDepartment of Mathematics and Statistics
Utah State University, Logan, UT, USAe-mail: [email protected]
&International Association for Statistical Computing (IASC),
President (2019–2021)
February 5, 2020
Jürgen Symanzik — February 5, 2020 International Scientific and Practice Conference, Sankt–Peterburg, Russia 1
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Outline
1 Eye-Tracking & EyeTrackR R Package
2 The Posture Study
3 EDA
4 Statistical Tests for Eye-Tracking Data
5 Conclusions and Outlook
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Development
Eye trackers first built in the late 1800s.Eye tracking techniques developed rapidly during the pastcentury.Video-based pupil and corneal reflection tracking method are thedominating eye tracking method since early 1990s.
The identified pupil (white cross-hair) and corneal reflection (black cross-hair).(Previously published in Holmqvist et al. 2011).
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Applications
Education: Solving problems, classroom presentations, reading,and looking at graphics.Usability Research: Reading behaviors online, searching,scanning online information, and web page design.Sports: Studying basic technical mistakes in hand-eyecoordination and how to optimize performance in soccer, tabletennis, shooting, hockey, and baseball.Psychology: Understanding how people gather informationvisually and how information is processed, e.g., research inautism.Marketing: Understanding of consumers’ willingness topurchase goods or services.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Mobile Eye Tracker
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Recording Scene
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Areas of Interest (AOI)
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Data Recording: Single Frame
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Crosshair Matching: Single Frame
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
The Posture Study: Primary Research Questions
Does judging the action capabilities of another person dependon one’s own experiences?Background: Action anticipation must be present wheninteracting with others (e.g., to avoid collisions, pass somethingon to someone, etc.).Motivated by research in the Kinesiology and Health ScienceDepartment at Utah State University (USU).
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Participants
Group 1 (Control Group): 20 students with minimal experiencewith actions that require stability (e.g., yoga, gymnastics, . . .)from the undergraduate psychology student pool at USU.Group 2 (Treatment Group): 20 students with extensive yogaexperience from advanced yoga classes at USU.Analysis still ongoing. Preliminary results presented here.See Symanzik et al. (2017 & 2018), for further details on thisstudy.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Anticipated Outcomes
Those with extensive yoga experience will judge an actor to bemore stable than those without stability-specific experience.The visual information (i.e., viewing patterns) used to judgestability will differ between different groups of individualswith unique action experiences.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Apparatus and Tasks
22 pictures of a single actor holding a posture.All postures shown to each participant in random order.Participants have to judge the stability of each posture, i.e., howlong the person could hold the posture.Participants wear an ASL portable eye-tracking device thatrecords the viewing patterns.Extract information from the eye-tracking videos via theEyeTrackR R package (Li, 2017; Li & Symanzik, 2016, 2017).
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Postures 1 to 6 (out of 22)
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Statistical Analysis
What are within groups similarities /differences (if any) of theviewing patterns for each posture / for all postures?
What are between groups similarities / differences (if any) of theviewing patterns for each posture / for all postures?
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Posture 8: Similar Viewing Patterns (2 Participants) [Heatmaps]
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Posture 17: Different Viewing Patterns (2 Participants) [Heatmaps]
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
The Syrjala (1996) Test
Tests for a difference between the spatial distributions of twopopulations.Sensitive to differences in the way the populations are distributedacross the study area, but insensitive to differences inabundance between the two populations.Frequently used for wildlife sample surveys and epidemiology;rarely used for eye-tracking so far (e.g., Chetverikov et al., 2018).Here: Applied to the viewing patterns from pairs of participantsusing 5 × 5, 10 × 10, and 20 × 20 grids and 25, 100, and 400random point locations obtained from a sequential spatialinhibition (SSI) process.Caveat: Results of Syrjala’s test highly depend on type of dataconversion (grid vs. random points) and number of grid cells ornumber of random cells, respectively (see McKinney andSymanzik, 2019).
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
The Modified Syrjala Test (McKinney and Symanzik, 2019)
Combine the labeled data.Center the data using a bivariate median.Calculate the weighted modified Syrjala statistic.Rotate the data about the bivariate median.Recalculate the weighted modified Syrjala statistic on the rotateddata.Repeat through 360◦.Permute the data and repeat calculations of the statistic acrossall of the rotated data.Compute the permutation test p-value.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
A Comparison of Two Bivariate Dot Plots
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Visualization of Calculations within the Modified Syjrala Statistic
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Postures 1 and 9: Scatterplots of Viewing Patterns (2 Participants)
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Posture 1: AOIs of Viewing Patterns (2 Participants)
Modified Syrjala-based p-value: 0.172 (based on 36 rotationsand 999 permutations).AOI χ2-based p-value: 0.3296.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Posture 9: AOIs of Viewing Patterns (2 Participants)
Modified Syrjala-based p-value: 0.001 (based on 36 rotationsand 999 permutations).AOI χ2-based p-value: 0.2745.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Interpretation of Test Results
Results of original Syrjala’s test highly depend on type of dataconversion (grid vs. random points) and number of grid cells ornumber of random cells, respectively.Our modified Syrjala test behaves more stable and providessimilar results, even for different number of rotations.Occasional noticeable differences between modifiedSyrjala-based p-value and AOI χ2-based p-value — needsfurther investigation.Extend quantitative analysis to entire groups, comparingtreatment group with control group for each of the 22 postures.Consider different forms of weighting for different viewinglengths.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
References
Chetverikov, A., et al. (2018). Implicit Processing During Change Blindness Revealed with Mouse-contingent andGaze-contingent Displays. Attention, Perception, & Psychophysics, 80(4):844–859.
Holmqvist, et al. (2011). Eye Tracking: A Comprehensive Guide to Methods and Measures, Oxford, New York: OxfordUniversity Press.
Li, C. (2017). Extracting and Visualizing Data from Mobile and Static Eye Trackers in R and Matlab. PhD Thesis, UtahState University.
Li, C. and Symanzik, J. (2016). The Linked Microposter Plot as a New Means for the Visualization of Eye TrackingData. In 2016 JSM Proceedings, Alexandria, VA: American Statistical Association. (CD).
Li, C. and Symanzik, J. (2017). EyeTrackR: An R Package for Extracting and Visualizing Data from Mobile and StaticEye Trackers. In 2018 JSM Proceedings, Alexandria, VA: American Statistical Association. (CD).
McKinney, E. and Symanzik, J. (2019). Modifications of the Syrjala Test for Testing Spatial Distribution DifferencesBetween Two Populations. In 2019 JSM Proceedings, Alexandria, VA: American Statistical Association. (CD).
Symanzik, J., et al. (2017). Eye-tracking in Practice: A First Analysis of a Study on Human Postures. In 2017 JSMProceedings, Alexandria, VA: American Statistical Association. (CD).
Symanzik, J., et al. (2018). Eye-tracking in Practice: Results from a Study on Human Postures. In 2018 JSMProceedings, Alexandria, VA: American Statistical Association. (CD).
Syrjala, S. E. (1996). A Statistical Test for a Difference Between the Spatial Distributions of Two Populations. Ecology,77(1):75–80.
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Eye-Tracking & EyeTrackR R Package The Posture Study EDA Statistical Tests for Eye-Tracking Data Conclusions and Outlook
Questions ?!? —
or e-mail: [email protected]
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Eye-Tracking & EyeTrackR R Package
The Posture Study
EDA
Statistical Tests for Eye-Tracking Data
Conclusions and Outlook