Figure 4. 5 : Data Points for Six Transfer Scenarios
Same Block In Familiar Area |
Same Block In Unfamiliar Area |
1 Block In Familiar Area |
1 Block In Unfamiliar Area |
3 Blocks In Familiar Area |
3 Blocks In Unfamiliar Area |
The horizontal line in the diamond shape on the chart shows the mean of each set of data points, and the diamond shows the 95% confidence level of that mean. At a glance, one can see that the reported time savings required is much higher, in each category of distance and area familiarity, for the blind using their regular methods. The addition of auditory and spatial information makes those estimated data quite similar to that given by sighted respondents. The means diamonds for the sighted and the blind, when they considered RIAS, there is a large overlap, showing that there is no significant difference in their data. P values are discussed later.
Table 4. 9 Percent of Subjects with High Resistance to Transfe r Vehicles.
# of Extra Minutes Would Stay on Vehicle |
Percent of Subjects |
||
Blind Regular |
Blind W/ RIAS |
Sighted (control) |
|
60 (no transfer) |
18% |
1% |
3% |
40 or more |
36% |
2% |
5% |
30 or more |
71% |
16% |
7% |
Table 4. 10 Mean Responses for Six Transfer Scenarios
Mean Saved Time To Make a Transfer |
||||
Area |
Subject Type |
Same Block |
1 Block |
3 Blocks |
Familiar |
Blind, Regular Method |
18.3 |
23.5 |
33.0 |
Blind, with RIAS |
11.5 |
13.9 |
20.0 |
|
Sighted |
11.6 |
13.1 |
20.8 |
|
Unfamiliar |
Blind, Regular Method |
27.0 |
33.8 |
44.0 |
Blind, with RIAS |
13.7 |
16.9 |
23.8 |
|
Sighted |
12.1 |
14.0 |
23.0 |
Figure 4. 6 Transfer Decisions in a Familiar Area
Figure 4.7 shows the data for three subject groups making a transfer in
an unfamiliar area. The results look quite similar to the familiar area,
although the initial resistance and slope of distance decay is higher for
each group. There was a highly significant difference between transfer
behavior reported by the sighted and by the blind subjects using their normal
technique (p<.0001 or less for all three distances). After the blind
subjects used RIAS in the experiment, they reported much different perceived
transfer-making behavior.
Figure 4. 7 Transfer Decisions in an Unfamiliar Area
Unfamiliar areas present problems when cues, paths, and locations must be
learned over time. Figure 4.8 compares the mean reported times for
the three groups in both the familiar and unfamiliar areas.
Sighted respondents reported little difference between familiar and unfamiliar
areas, and no significant difference was found (p <.16, 0.13, and 0.12,
respectively for the same block, 1 block, and 3 blocks). The effect
of unfamiliar environments on the people with vision restrictions is strongly
shown demonstrated by a comparison of their estimated transfer behavior.
Same block times went from 18.3 minutes to 27.0, 1 block times from 23.5 to
33.8, and 3 block times from 33.0 to 44.0 minutes when comparing familiar
and unfamiliar transfer areas. The difference in the two familiarity
conditions, for the subjects using their regular methods, was highly significant
(p <.001 or less for all three distance measures). Even with the
vastly lowered estimated time for transfer behavior after using RIAS, the
effect of area familiarity was still in effect, although not nearly as strong.
Same block times went from 11.5 minutes to 13.7, 1 block times from 13.9 to
16.9, and 3 block times from 20.0 to 23.8 minutes when comparing familiar
and unfamiliar transfer areas. The data on area familiarity differences
were significant (p <.002 or less for all three distance measures).
Figure 4. 8 Effect of Area Familiarity on Perceived Transfer Decisions
Table 4. 11 Linear Model for Making Transfers
Familiar Environment |
Unfamiliar Environment |
|||||
Intercept |
Slope |
Intercept |
Slope |
|||
Initial Time Resistance |
Time per Block |
Initial Time Resistance |
Time per Block |
|||
Blind, Regular |
R= |
18.5 + |
4.9D |
R= |
27.5 + |
5.6D |
Blind with RIAS |
R= |
11.3 + |
2.9D |
R= |
13.7 + |
3.4D |
Sighted (control) |
R= |
11.0 + |
3.2D |
R= |
11.3 + |
3.7D |
Figure 4. 9 Distance Impedance per Block
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