Hazard anticipation of young novice drivers - SWOV

5.3.3. Procedure
Participants were seated approximately 60 cm from a 17'' LCD-screen (aspect
ratio 4:3). The resolution was 1024 × 768. The videos were presented full
screen. This provided participants with a horizontal field of about 32°. Before
participants started, they watched the instruction video and they practiced
with two trial video clips. The instruction phase took on average five
minutes. The videos were presented in a fixed order as the computer
software did not allow for changes of the order. The time to complete the
task was on average twenty-five minutes. After the task was completed
participants filled in a short questionnaire with questions about
demographics, their driving experience and their computer experience,
including experience with computer games. Participants received no
financial reward for their participation.
5.3.4. Data analysis and design
A between-groups design was applied. Before the actual testing on
significance of differences between groups (p < .05), the sample was tested on
the assumptions for parametric testing (normal distribution and
homogeneity of variance). These assumptions were met. Prior to the
statistical analysis, the internal consistency reliability (Cronbach's α) was
considered. The t-test for independent samples was applied to test for
significant differences between the groups. To test whether experience of
computer games and age had an effect on the scores, univariate analysis of
covariance (ANCOVA) was applied. Besides significance of results, the effect
size (Partial èta squared, η 2 P
) was considered with η 2 P
= .01 as a small, η 2 P
=
.06 as a medium, and η 2 P
= .14 as a large effect size (Cohen, 1988).
The videos used in Study 2 were partly the same as the videos used in the
study reported in Chapter 4. For one video clip with a covert latent hazard, a
comparison was made between the recorded fixations of learner drivers
(both young learner drivers and older learner drivers) and experienced
drivers in Chapter 4 and the position of the mouse clicks made by learner
drivers and professional drivers in Study 2. This video clip is covert latent
hazard 6 in Appendix 1. The participant driver is turning left and can only
see possible oncoming traffic in the lane to the right of the lorry at the very
last moment. A video clip with a covert latent hazard was chosen because a
significant difference was found in Chapter 4 between learner drivers and
experienced drivers in fixations on areas where nothing can be seen, but
from where a covert latent hazard may emerge, with experienced drivers
189