visual perception of international traffic signs: influence of e-learning and culture on eye...
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Visual Perception of International Traffic Signs:
Influence of e-Learning and Culture on Eye Movements
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Gergely Rakoczi
Andrew T. Duchowski
Helena Casas-Tost
Margit Pohl
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA 2
Authors
Gergely Rakoczi
Andrew T. Duchowski
Helena Casas-Tost
Margit Pohl
Vienna University of Technology
Vienna University of Technology
Clemson University
Universitat Autónoma de Barcelona
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
Besides eye tracking …
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2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• Study goals:
– Analysis of eye movements when viewing traffic signs within e-learning scenario
– Investigation of two levels of learner’s preparation (absent or given teaching materials)
– Cultural differences expressed by eye movements
• Why? Motivation:
– Improvement of visual efficiency, user experience in e-learning, usability, HCI of e-learning environments
– (collecting more) recommendations for better design
– Better perception of traffic signs in driving education systems
– E-learning is becoming increasingly important for obtaining drivers license
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So, but now …
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Related work
• Eye tracking & Driving
– Studies almost exclusively on visual attention when performing act of driving
• Recognition of traffic signs in various conditions
• Eye movements in driving simulators, drivers‘ fatigue, etc.
– Yan, Guan and Xu: predict the visual perception of traffic signs
• effective for letters and symbols, but not for complex signs
– Ng and Chan: questionnaire on Chinese traffic signs
• 5 cognitive design aspects (familiarity, simplicity, …)
• But: no eye movements
http://www.engineeringletters.com/issues_v14/issue_1/EL_14_1_3.pdf
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Related work
• Eye tracking & prior preparation
– Numerous reports on effect of task instruction on eye movements
– E.g reading, visual scene perception (Yarbus)
– Amadieu, Van Gog, Paas, Tricot, and Mariné: Studies on learner’s level of preparation – related to novices and experts
• Eye tracking & e-learning
– Only few eye tracking studies on e-learning systems
– Contextually related are tests on perception of multimedia (text, images, simulations …)
– (fewer) usability tests
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Related work
• Eye tracking & Culture
– Chua, Boland and Nisbett: Cultural differences in scene perception
• Different visual strategies for Westerners and Easterners
• Westerns (Americans) fixate faster and longer on foreground and perceive more visual details
• Easterners (Chinese) tend to move eye a holistic manner
– Hellige and Cox: evidence from reading
• English left-hemispheric dominance more sequential/analytic (attention on single letters)
• Chinese right-hemispheric dominance holistical(attention on entire configuration of characters)
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Methodology
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Procedure
• 3 x 2 x 2 mixed factorial design
• Between-subjects factors
– Ethnicity (Austrian, Chinese, American)
– Teaching materials (absent, given)
• Within-subject factor
– Sign origin (foreign, domestic signs)
• Study blocked by task types (matching, search, true/false)
• Pairwise comparison using t-test (pooled SD and Bonferronicorrection)
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• All Test items Counter-balanced via Latin square in TUWEL
• Mixed and homogeneous tasks
Procedure
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Eye Metrics
• Eye tracking metrics in focus:– Total gaze duration
– Time to first fixation
– Total fixation count
– Mean fixation duration
– Overall regression rate on traffic signs
– Task success rate Overall Results
Search Tasks
Mixed
Task Scenario
Homogeneous
Task Scenario
Mean fixation duration
Gaze duration
Task success rate*
Regression rate
Fixation count
Matching Tasks
Gaze duration
...
Mixed
Task Scenario
Homogeneous
Task Scenario
True/false Tasks
Mixed
Task Scenario
Homogeneous
Task Scenario
Gaze duration
...
Gaze duration
...
Gaze duration
...
Gaze duration
...
(for each) Parameter:
Teaching material
Sign origin
Ethnicity
Time tofirst fixation
* … not an eye tracking metric
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• Two labs, both equipped with Tobii (50 series)
• 50 Hz, 1280x1024, no chin rest …
• Manual calibration using 9-point grid
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Apparatus
AustriaUSA
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• TUWEL (e-learning environment of my home university)
• Based on
• System Languages:
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Stimulus
German English Chinese
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• Test involved different task types:
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Tasks and Groups
Search task True/false task Matching task
• Treatment group received
teaching lessons prior to the test
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• Austria: closest to the international norm
• China: similar to norm, but changes in coloring
• USA: no adoption of the international norm, differences in coloring, shape and style
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Traffic signs
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• 3 countries of 3 different continents– Europe (Austria)
– North America (USA)
– Asia (China)
• N=36
• 12 from each country
• 6 females, 6 males for each country
• 3 of male/female of each country in treatment group (teaching lessons) for balance
• Average age: 26.3 (between 22 and 34)
• Recruitment criteria: driving license
• Additional recruitment criteria for Chinese
• 3 experiments excluded (calibration difficulties)
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Participants
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
Results
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2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• No significant influence of prior preparation
• Possible reasons?
– Were teaching lessons confusing? Low quality?
– Not really, …Questionnaire revealed that online instructions perceived rather simple than
complex, easy to understand and rather useful than unusable. Low standard deviation indicates coherency among participants’ feedbacks.
– Participants’ level of knowledge on traffic signs already high prior to the study
• average of 7 years of driving experience
• Rather cognitive heuristics were used to solve tasks
– … or did participants skipped reading them?
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Influence of teaching materials
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Teaching material 1
Teaching material 2
Austrian American Chinese
Influence of teaching materials
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• strong influence for all metrics AND task types
• strongest effect on search tasks, weakest on true/false tasks
• Foreign signs provoke …
– longer gaze duration & lower scores,
– higher fixation counts & regression rates
– Lower times to first fixation (out-of context object?)
– longer mean fixation durations
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domestic (Chinese) foreign (American) foreign (Austrian)
Same participant!
Influence of sign origin
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Matching task Austrian heatmap
Chinese heatmap American heatmap
• Most significant results for eye movement in mixed scenarios
Different participants!
Influence of sign origin
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• Similar among all conditions
• Exception: significantly lower for every task type and scenario for Americans
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Culture: mean fixation durations
• Interesting: Chinese fixated almost twice as fast on traffic signs
• Visual strategies to fixate faster on all elements to get overview
• Or Chinese more likely to be distracted by figurative visuals?
Culture: time to first fixation
2013 Aug. 29th - Gergely Rakoczi et al @ ETSA
• Corroborate the finding foreground objects, retrieve more visual detail
• Differences in motivation, concentration, impatience, expertise?
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Chinese gazepath Austrian gazepath
American gazepathTrue/false task
Example: US mean fixation durationsDifferent participants!
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Usability issues
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• “Americanized” Chinese participants
• 12 participants per ethnic group “weak”
for statistical significance
• The driving experience of Chinese participants was more than half of Austrians and Americans
• Narrow group of participants (students, alumnis only)
• Not 100% real test scenario, as conducted in lab
• Eye tracking data is very “noisy”– the more complex the stimulus gets …
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Limitations
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Thanks for listening … Questions?
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References• Ko, M., Higgins, L., Chrysler, S.T., Lord, D. 2010. Effect of driving
environment on drivers’ eye movements: Reanalyzing previously collected eye-tracker data. Technical Report. 89th Annual Meeting of Transportation Research Board.
• Inman, V.W. 2012. Conspicuity of traffic signs assessed by eye tracking and immediate recall. In Proceedings of the Human Factors and Ergonomics Society Annual Meeting 56, 2251-2255.
• Kaakinen, J.K., Hyönä, J. 2010. Task effects on eye movements during reading. Journal of experimental psychology. Learning, memory, and cognition 36, 6, 1561-6.
• Nielsen, J., Pernice, K. 2010. Eyetracking Web Usability. Voices That Matter. New Riders, Berkeley.
• Holmqvist, K., Nyström, M., Andersson, R., Dewhurst, R., Jarodzka, H. 2011. Eye Tracking: A Comprehensive Guide to Methods and Measures. Oxford University Press, Oxford.
• Amadieu, F., Van Gog, T., Paas, F., Tricot, A., Mariné, C. 2009. Effects of prior knowledge and concept-map structure on disorientation, cognitive load, and learning. Learning and Instruction 19, 5, 376-386.
• Chua, H.F., Boland, J.E., Nisbett, R.E. 2005. Cultural variation in eye movements during scene perception. In Proceedings of the National Academy of Sciences of the United States of America 102, 35, 12629-12633.
• Hellige, J.B., Cox, P.J. 1976. Effects of concurrent verbal memory on recognition of stimuli from the left and right visual fields. Journal of Experimental Psychology: Human Perception and Performance 2, 210-221.
• Tan, L.H., Liu, H.L., Perfetti, C.A., Spinks, J.A., Fox, P.T., Gao, J.H. 2001. The neural system underlying Chinese logograph reading. NeuroImage 13, 836-846.
• Ng, A.W.Y., Chan, A.H.S. 2007. Cognitive design features on traffic signs. Engineering Letters 14, 13-18.
• Yan, H., Guan, H., Xu, Z. 2011. Incorporating Saliency Map into Prediction of Drivers’ Eye Fixations on Traffic Signs. In 11th International Conference of Chinese Transportation Professionals. American Society of Civil Engineers, Reston, 1627-1639.
• Just, M.A., Carpenter, P.A. 1976. Eye fixations and cognitive processes. Cognitive Psychology 8, 441-480.
• Bente, G. 2005. Erfassung und Analyse des Blickverhaltens. In Lehrbuch Medienpsychologie, Bente, G., Mangold, R., Vorderer, P., Eds. Hogrefe, Vienna, 297-324.
• Rakoczi, G. 2012. Eye Tracking in Forschung und Lehre: Möglichkeiten und Grenzen eines vielversprechenden Erkenntnismittels. In Digitale Medien, Reichl, F., Csanyi, G., Steiner, A., Eds. Waxmann Verlag, Münster, 87-98.
• Jacob, R.J.K., Karn, K.S. 2003. Eye Tracking in Human Computer Interaction and Usability Research: Ready to Deliver the Promises. In The Mind’s Eye: Cognitive and Applied Aspects of Eye Movement Research, Hyönä, J., Radach, R., Deubel, H., Eds. Elsevier Science, Amsterdam, 573-605.
• Salvucci, D.D., Goldberg, J.H. 2000. Identifying Fixations and Saccades in Eye-Tracking Protocols. In Eye Tracking Research & Applications (ETRA) Symposium. ACM, Palm Beach Gardens, 71-78.
• Goldberg, J.H., Kotval, X.P. 1999. Computer interface evaluation using eye movements: methods and constructs. International Journal of Industrial Ergonomics 24, 6, 631-645.
• Ehmke, C., Wilson, S. 2007. Identifying web usability problems from eye-tracking data. In Proceedings of the 21st British HCI Group Annual Conference on People and Computers: HCI. British Computer Society, Swinton, 1, 119-128.