1. Application: driving Gemma Briggs
Eye Tracking research
Application: driving
Gemma Briggs

2. What eye movements tell us…and what they don’t
They tell us…
areas of interest
number of fixations for a given time
scan patterns and hot spots, etc.
They don’t tell us…
What information the viewer is extracting upon fixation
What is happening in the brain whilst the person is viewing a scene
If perception has occurred

3. Distraction and eye movements
Increased cognitive workload leads to changes in visual scanning patterns.
Tunnelled vision
Task demands can dictate visual behaviour
Individuals may be unaware of such changes
People can look but not see (LBFS errors)

4. Driving research How does visual behaviour alter when dual tasking?
Do different types of secondary tasks affect eye movements differently?
What elements of the secondary task are most distracting?
How do we allocate out attention?
Can we learn to moderate behaviour?

5. Imagery experiment
View films from driver’s perspective. Some contained hazards (central or peripheral), some didn’t. Participant had to react when they saw a hazard
Half also completed a secondary, concurrent, imagery task via hands free telephone.
Eye movements measured
scan patterns (position of hazard)
Variance of fixations in given time frame
Areas of interest
Reaction times for hazards
Number of hazards reacted to
Explain imagery context first.

7. Results
Controls detected significantly more hazards than dual taskers (DT).
For those hazards they detected, DTs took significantly longer to react than controls.
For all central hazards, DTs took significantly longer to react than controls
No sig difference in RTs between controls and DTs for peripheral hazards……but that’s because the DTs didn’t perceive them!

8. Results DTs made significantly more LBFS errors than controls
More results based on position of hazard and fixation variance. E.g. when imagery task led fixation away from position of hazard. Sig effects but no time to discuss!

9. Results
Significant difference in variance of fixations between controls and DTs: controls increased eye movements when a central hazard was presented , DTs decreased their eye movements.
Controls showed wider range of fixations.
DTs demonstrated visual tunnelling

10. Representative examples
Undistracted Dual tasking
Round up: imagery can selectively interfere with visual perception in a driving scene. Eye movements are affected by increased CWL. Cognitive and visual tunnelling can occur resulting in poorer overall driving performance. Moving on to look at forensic applications using the flicker paradigm shown earlier, along with a change blindness approach to the weapon focus effect.

11. Things to consider You get a LOT of data from eye tracking!
Need a good sample size
Data collection can take a long time…but it’s worth it
Need really clear research questions from the outset
You won’t need a lot of the data you collect!
Think carefully about how you will analyse your data
Be careful about the conclusions your draw

12. Thank you!