Mobile Phone Use in a Driving Simulation Task: Differences in Eye Movements

1. Mobile Phone Use in a Driving Simulation Task: Differences in Eye Movements Stacy Balk, Kristin Moore, Will Spearman, & Jay Steele

2. The Problem • Each year there are nearly 43,000 traffic collisions (NHTSA, 2005) • Traffic crashes are responsible for 40 percent of deaths of people aged 15-20 (National Transportation Board, 2005) • Inattention is the most sighted cause for traffic crashes (NHTSA, 2000)

3. Background • When driving, & mental workload is increased (e.g. high traffic, visual clutter, etc.) drivers are less able to maintain high situation awareness. • A reduction in situation awareness may result in a lowered ability to optimally perform driving tasks (Gugerty 1997).

4. Background Cont. • In addition to normal aspects of driving, conversing on mobile phones has been shown to dramatically increase mental workload (Recarte & Nunes, 2003). • This is especially troubling due to the recent increase in the popularity of mobile phones (Incisive Interactive Marketing, 2005)

5. Background Cont. • 85% of all mobile phone owners talk on their phones at least occasionally while driving (NHTSA, 1997) • 21% of crashes or near crashes reported by respondents involved at least one driver using a mobile phone (Seo & Torabi, 2004).

6. Previous Work • Strayer & Johnston (2001) found participants who used a mobile phone (both hand-held and hands free) performed worse in a driving task compared with participants who passively listened to radio broadcasts or books on tape. • Thus the ‘hands’ aspect is not what degrades driving performance

7. Previous Work cont. • Strayer et al. found that people that talking on mobile phones in a driving task were more likely to experience ‘looked-but-failed-to-see’ errors (2003) • Crundall et al. (2004) found that people talking on mobile phones have shorter fixation durations – which may account for ‘looked-but-failed-to-see’ errors

8. Previous Work cont. • It has been well established that talking while driving degrades driving performance. • It is not known, however, which aspects of ‘good’ driving are affected when talking on a mobile phone while driving (Gugerty, 2004)

9. Purpose • Engaging in TMWD increases driving errors as well as ‘looked-but-failed-to-see’ errors, it is not known how visual search strategies are modified according to the specific driving task. • The current study sought to quantify if/how visual search patterns change while engaging in a mobile phone conversation as well as combined with potentially hazardous driving situations

10. Participants • 16 (11 female) Clemson University undergraduate students • 20/20 or corrected to 20/20 vision • A valid drivers’ license • At least 2 years driving experience (M = 3.5 years). • One person was not able to participate due to poor tracking

11. Apparatus • Tobii 1750 eye tracker • Sampling rate of 50 hertz • 1280 x 1024 display 17 LCD screen

12. Design • Between subjects, 2 x 2 design. • 8 people (3 male, 5 female) participated in the mobile phone condition • 8 people (2 male, x 6 female) participated in the non-mobile phone condition. • All participants viewed 12 trials with 4 vehicles and 12 trials with 7 vehicles in the driving scene.

13. Development of the Driving Simulator • C++, OpenGL, SDL • Dynamic ROI generation • Synchronization of frame rate and eye tracker • Mirrors

14. Language task • Pimsleur Japanese language learning compact disk set for beginners • 3 language aspects: • Listening • Repeat • Generate • Synced to begin and end with each driving scene

15. Procedure • Participants were given instructions • Practice trials • Calibration • View trials (people in the mobile phone task ‘spoke’ simultaneously) • Answered a question about what occurred during the scene • Confidence in their response

16. Procedure • After the completion of the 24 trials, people responded to a questionnaire about their attitudes and thoughts about mobile phones

17. Results • People on the mobile phone answered fewer questions about the scene correctly F (1, 14) = 49.594, p < .001 (37% vs. 68%) • People in the non-mobile phone group were more confident in their responses F (1, 200) = 23.314, p < .001. (4.03 vs. 3.18) • Overall people answered more questions with 4 vehicles correctly than with 7 F (1, 380) = 11.861, p = .001. (60% vs. 44%)

18. Results

19. Survey Results • All participants owned a mobile phone • On average, participants reported using their mobile phone ‘sometimes – often’ while driving • 4 participants reported using their phone nearly every time they drove. • All felt others’ driving performance is degraded while TMWD • However, 7 of the 16 participants felt their driving performance was only degraded slightly or not at all

20. Eye Data Analysis • Removed bad data • Velocity filter to determine fixations and durations • ROI output from driving simulator compared with fixations

21. Mobile Phone Fewer total valid points Percentage of fixations of total eye points were not different No Mobile Phone Larger number of total fixations The spread of the fixations were not different Eye Data Results - Overall

22. Mobile Phone Less time spent in the ROI Duration of fixations was less (supports looked-but-failed-to see hypothesis) No Mobile Phone More fixations in the ROI Eye Data Results – ROIs over whole task

23. Mobile Phone Less time spent in the ROI Duration of fixations was less (supports looked-but-failed-to see hypothesis) No Mobile Phone More fixations in the ROI Eye Data Results – ROIs during the event

24. Discussion • Language task: • Controlled speed of conversation • Interest level • Etc. • Low-fidelity vs. high fidelity simulator • Eye-data ‘thinking’ phenomenon

25. Conclusions / future work • People may not be aware of decreased performance when TMWD • Repeat the expt. with a more ‘involved’ task • Examine the validity of the language task

26. Questions!