1 Cell Phone Induced Perceptual Impairments During Simulated Driving David Strayer, Frank Drews, Robert Albert, and William Johnston Department of Psychology University of Utah

2 Every 30 minutes someone dies on our highways because they didn’t pay attention while driving Our research focuses on one potential contributor to distracted driving Does conversing on a cell phone interfere with driving?

3 Do Cell Phones Interfere With Driving?

4 Driver Inattention & Cell Phones Currently 120 million cell phone subscribers in US 60% of cell phone time is spent while driving Tens of millions of people driving while using the cell phone each day Anecdotal evidence suggests that cell phones interfere driving

5 Research Questions Does conversing on a cell phone interfere with driving? How significant is the interference? What are the causes the interference? - Peripheral interference (dialing, holding the phone) - Attentional interference (cell phone conversation) Legislative initiatives tacitly endorse the peripheral interference hypothesis

6 Epidemiological Studies Redelmeier & Tibshirani (1997) New England Journal of Medicine - p(cell phone in use | accident) = fold increase in risk -- comparable to DUI - No advantage of hands-free phones Increased risks associated with inattention, rather than dexterity Limitations: correlational, self selection, intervening variables

7 Simulator Study I Conditions - Hand-Held Cell Phone - Hands-Free Cell Phone - Radio Control - Book on Tape Control Conversations - Clinton Impeachment - Olympic Bribery Scandal Driving & Conversation Driving Warm-up 36 minutes

8 Response to Simulated Traffic Signals Subjects responded to red and green traffic signals Measures: - Probability of missing signals - Reaction time to detected signals Preliminary Analysis - Hand-Held = Hands-Free - Radio Control = Book on Tape Control

9 Cell Phone Control SingleDual

10 Simulator Study I

11 Simulator Study I

12 Conclusions Using a cellular phone while driving impairs performance - Twice as likely to miss critical/unpredictable events - Slower to react to critical/unpredictable events Cell phone conversation itself causes the interference Hands-free phones do not appear to be the solution, because the deficits appear to be due to attentional demands imposed by the conversation

13 Does the Cell Phone Conversation Affect What We “See” While Driving? Measured perceptual memory for objects presented at fixation - While driving alone - While driving and conversing on a hands-free cell phone Phase I -- Same as Study I, except words were presented at fixation and subjects were to respond if the word was an animal Phase II -- Measured the implicit perceptual memory for these words using dot clearing paradigm

14 Dot-Clearing Procedure

15 Simulator Study II Conditions: - Single-task words (driving only) - Dual-task words (driving & phone) - Control words Measures: Time to correctly identify word

16 Simulator Study II Baselin e

17 Simulator Study II Divided Attention Costs

18 Conclusions for Study 2 Impaired perceptual memory for objects presented while driving and conversing on a hands-free cell phone The cell phone conversation alters how you perceive the driving environment by diverted from driving to other engaging activities

19 Ongoing Simulator Studies

20 Ongoing Simulator Studies Hands-free cell phone conversations -- call initiated before driving Cell phone conversations interfered with driving - Drivers reacted slower to cars braking in front of them - Drivers were 4 times more likely to get in traffic accidents Driving interfered with cell phone conversations - Impaired memory of conversation - Poorer decision making

21 Future Directions How do other advanced technologies affect driving performance?

22 Conclusions

23 Future Directions How does this compare with conversations with passengers in the car? How does the nature of the conversation modulate the effect? How does this compare with driving under the influence of alcohol? How does expertise affect these divided attention deficits? Are these deficits exacerbated with age? How great are the individual differences in distraction?

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