Geography Reference
In-Depth Information
value will correspond to a different fixation duration. This problem is also described
in more detail in Ooms et al. (
2014
).
To overcome this problem, a grid of Areas of Interests (AOIs) will be used to
visualise the fixations: their count and total duration in each cell. This allows
comparing the overall fixation counts and durations between the two mediums in
a more objective way. The selected colour ramps to visualise the data will not be
based on one stimulus, but on the values of all stimuli.
The dimensions of the grid cells is based on the size of the stimulus (which is
equal for all stimuli) and the accuracy of the eye tracker. The original screen had a
resolution of 1,920
1,080 pixels. However, the actual map image was displayed
on 1,400
880 pixels. The accuracy that could be reached by the eye tracker, when
considering the 1
deviation limit, was 2.02 cm. Based on these measurements it
was decided to use square sized AOIs of 40
40 pixels (or 2.30 cm on the screen).
This results in a grid of 35
22 cells. As was mentioned in section “Methodology”,
the grid with the corresponding values (fixation counts and durations) was obtained
by applying the JAVA-tool
fr2grid
(which converts the exported fixation report
from OGAMA to a grid). The resulting grid was visualised in Excel using the
'
conditional formatting
options. The results are discussed in the next section.
'
Result
Search Times
During each trial the participants had to locate three names in the map image. The
registered search times can indicate the efficiency with which these names were
located (Nielsen
1993
; Rubin and Chisnell
2008
). The mean search time over all
test persons and stimuli (paper and digital) is 146.842 s (SD
¼
97.367 s). The mean
search time for paper maps (M
68) is somewhat
higher than for digital maps (M
¼
146.391 s, SD
¼
78.054 s, N
¼
70). However,
statistical analyses (t-test) indicate that no significant difference could be found
between both mediums (P
¼
147.306 s, SD
¼
114.500 s, N
¼
.05). The mean search times and associated
standard deviations for each stimulus are listed in Table
4
. No trend can be detected
in this table.
¼
0.956
>
Fixation Count
The mean fixation count (number of fixations per second) over all participants and
stimuli is 3.139 fix/s (SD
¼
0.409 fix/s). The mean fixation count is lower on paper
stimuli (M
¼
2.981 fix/s, SD
¼
0.402 fix/s, N
¼
68) than on their digital counterparts
(M
¼
3.293 fix/s, SD
¼
0.356 fix/s, N
¼
70). The statistical t-test indicates that this
