Eye Tracking research
Application: driving
Gemma Briggs
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
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)
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?
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
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!
Results
• DTs made significantly more LBFS errors than
controls
Mean # LBFS errors made
3
2.5
2
1.5
1
0.5
0
Control
Condition
DT
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
Representative examples
Undistracted
Dual tasking
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
Thank you!