Application: driving Gemma Briggs 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 Explain imagery context first.

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 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!

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 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.

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!