Transcript Field dependence and driver visual search behavior

Field dependence and driver
visual search behavior
Professor: Liu
Student: Ruby
Objective
• To investigate the field dependence
driver’ visual search behavior on
different road and time of day.
References
• Goodenough, 1976
– Field dependence drivers were related to
accidents.
– Field independence drivers may avoid
accidents.
References
• Kaluger and Smith, 1970; Mourant and
Rockwell, 1972; Zell, 1969:
– This is an relationship between eye
movement and the driver performance
which were field dependence/ independence.
Experiment 1: eye movements in
curve negotiation
• Purpose
– To identify the perceptual search method
involved in curve through and try to get the
curves’ accident rate.
• Hypothesis
– The field dependent drivers have the less
efficient, and the visual search may be
focused on less informative information.
Experiment 1: eye movements in
curve negotiation
• Participants
– 5 students. (3 male and 2 female)
• Equipment
– Eye tracking and experimental vehicle.
• Procedure
– Two lane highways in the country view.
– 22 curved road and two straight road.
– Keep an mean speed on 96 km/h.
Results and discussion
• The embedded figure test
– Two females got 15 s and 22s
– Three males got 27 s, 40 s, and 50 s.
• Two females and one male can be considered
field independent.
Results and discussion
Results and discussion
• The EFT scores and the mean to peak power
ration was 0.99.
– The more field dependence drivers were more
focused in a small part on the visual field.
• The EFT scores and the median frequency was
-0.91.
– The field dependence drivers had the slow visual
search which they need more time to search the
traffic environment.
Results and discussion
• The field dependence drivers may have a
slight tunnel vision or the peripheral
vision capabilities may decrease.
• The field dependence drivers were hard
to pass the curve road which because
their perceptual load is increased.
Experiment 2 : age related changes
in drivers’ spare visual capacity
• Purpose
– To identify the age related participants’
information processing and the visual search
behavior.
Experiment 2 : age related changes
in drivers’ spare visual capacity
• Participants
– 6 younger people (ages 20-25)
– 9 older people (ages 63-70)
• Equipments
– The same equipments as in experiment 1.
Experiment 2 : age related changes
in drivers’ spare visual capacity
• Six information processing tests
–
–
–
–
–
–
Embedded figure test
Choice reaction time test
Visual search test
A sequential choice reaction test
A memory test
A movement-time test
• Four driving tasks
– Driving at normal speed in the clear traffic.
(daytime and nighttime)
– Car following at 80km/h.
(daytime and nighttime)
Results and discussion
• In the information processing test, only
EFT and the visual search test were
significant (r = 0.56) and related with
driving visual search.
• EFT
– The young drivers were field independent
drivers, they took 0.2 min finished the test.
– The older drivers were field dependence
drivers, they took 1.3 min finished the test.
Results and discussion
• Mean visual search time
– Younger drivers were 3.2 s.
– Older drivers were 2.3 s.
• Mean eyes open time
– Younger drivers were 0.7 s.
– Older drivers were 1.5 s.
Results and discussion
• When driver had longer meant time, they
have to keep his eye open on the road.
– The longer time to locate the simple figure
from the complex figure in EFT.
Conclusions
• The field dependence drivers took long
time to get relevant information and they
were hard to shift their attention to
another place.
• The field dependence drivers were hard
to get the important information from the
road environment and they may have an
higher accident.