Field dependence and driver visual search behavior

1
Field dependence and driver visual search behavior

• Professor Liu
• Student Ruby

2
Objective

• To investigate the field dependence driver
  visual search behavior on different road and time
  of day.

3
References

• Goodenough, 1976
• Field dependence drivers were related to
  accidents.
• Field independence drivers may avoid accidents.

4
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.

5
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.

6
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.

7
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.

8
Results and discussion
9
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.

10
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.

11
Experiment 2 age related changes in drivers
spare visual capacity

• Purpose
• To identify the age related participants
  information processing and the visual search
  behavior.

12
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.

13
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)

14
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.

15
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.

16
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.

17
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.