Measuring Cognitive

Distraction in the Vehicle

David StrayerUniversity of Utah

Multitasking and Driver DistractionMultitasking and Driver Distraction

“Any man who can drive safely while kissing a pretty girl is simply not giving the kiss the attention it deserves.”

-- Albert Einstein

FACT: People cannot successfully perform two attention-demanding tasks simultaneously without declines in performance on one or both tasks

The Driver Distraction TriadThe Driver Distraction Triad

Manual

Visual CognitiveHigh

Low

Moderate

Eyes off the Road

Hands off the Wheel

Mind off the Drive

An Example of Cognitive DistractionAn Example of Cognitive Distraction

Observational StudyObservational Study(Intersection Study – 56K Drivers)(Intersection Study – 56K Drivers)

Traffic Violations 26.5% Cell Phone Usage 10.2% OR: 2.21 (95% CI 2.09 to 2.33)

Cell Phone No Phone

Failed to Stop 2416 12567 14983

Stopped Appropriately

3332 38294 41626

5748 50861 56609

Basketball Counting TaBasketball Counting Tasksk

Report the pass count for team in white

Inattention-Blindness Inattention-Blindness

• Test for evidence of cell-phone induced inattention blindness

• High-fidelity driving simulator• Hands-free cell phone• Naturalistic conversation with confederate• Eye tracker

• Two phases to the study:• Phase 1: Single & dual-task driving• Phase 2: Recognition memory tests for

objects encountered while driving

Recognition Memory Given Fixation Recognition Memory Given Fixation

Encoding or Retrieval Deficits?Encoding or Retrieval Deficits?

• Encoding deficits• Reduced attention to perceptual inputs• Clear implications for traffic safety

• Retrieval deficits• Failure to retrieve prior episodes• Less clear implications for traffic safety

• Event-related brain potentials recorded to traffic brake lights• Single-task• Dual-task

Traffic-related Brain Activity Traffic-related Brain Activity Elicited by Brake Lights Elicited by Brake Lights

Time (Msec)

-200 0 200 400 600 800 1000 1200

Am

plit

ude V

Single TaskDual Task

Brake

Cognitive Distraction: Inattention BlindnessCognitive Distraction: Inattention Blindness

Successful Navigation to Rest Successful Navigation to Rest StopStop

Cell-Phone ConversationCell-Phone Conversation

Passenger ConversationPassenger Conversation

Are We Reaching a Tipping Point?Are We Reaching a Tipping Point?

Benchmarking Cognitive DistractionBenchmarking Cognitive Distraction

► How do we quantify cognitive sources of distraction?

► How can we use this information to inform public policy?

Benchmarking Cognitive DistractionBenchmarking Cognitive Distraction

• Sources of Driver Distraction• Baseline driving ★• Radio

• Book on tape

• Passenger conversation

• Hand-held phone conversation

• Hands-free conversation

• Voice messaging / e-mail (speech to text & text to speech)

• OSPAN task (memory/math task) ★★★★★

• Driving Simulator• On-Road Vehicle

A New Metric for Cognitive DistractionA New Metric for Cognitive Distraction

• Driving Simulator Measures• Brake RT• Following Distance• Brain Measures (ERPs to brake lights)• NASA TLX (mental workload)• Detection-Response Task (new ISO standard)

• RT to green light (20/80)• Miss rate • ERPs to green light

• On-Road Vehicle• NASA TLX (mental workload)• Brain Measures (ERPs to brake lights)• Detection-Response Task (new ISO standard)

• RT to green light (20/80)• Miss rate • ERPs to green light

The Detection-Reaction Time (DRT) taskThe Detection-Reaction Time (DRT) task

• The DRT Task• New ISO Standard

• 20% Green Targets• 80% Red Distractors• RT to Targets• Missed Targets• ERPs to Targets

Target Light

Microswitch

A New Metric for Cognitive DistractionA New Metric for Cognitive Distraction(DRT Reaction Time)(DRT Reaction Time)

A New Metric for Cognitive DistractionA New Metric for Cognitive Distraction(DRT Miss Rate)(DRT Miss Rate)

A 5-Star Rating SystemA 5-Star Rating System for Cognitive Distraction for Cognitive Distraction

Summary and ConclusionsSummary and Conclusions

• Three sources of Driver Distraction• Visual

• Manual

• Cognitive

• Cognitive Distraction• Inattention blindness

• Impaired recognition memory, suppressed ERPs

• Impaired visual scanning (tunnel vision)

Applied Cognition LaboratoryApplied Cognition Laboratory