Date post: | 16-Dec-2015 |
Category: |
Documents |
Upload: | kerry-hardy |
View: | 214 times |
Download: | 0 times |
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
Control DT0
0.5
1
1.5
2
2.5
Condition
Mea
n #
LBFS
err
ors
mad
e
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!