investigating the effectiveness of assistive technologies on situationally impaired users
TRANSCRIPT
Investigating the Effectiveness of Assistive Technologies on Situationally Impaired Users
David Lucas Hugo Nicolau
Tiago Guerreiro Joaquim Jorge
Evolution …
On the move
Always near us
@ Home
@ Work
Outdoors
In car
@ Coffee shop
@ Subway
Many contexts
CONTEXT
Leading to …
SIID Situationally-Induced Impairments and Disabilities
Visual Attention
“Functionally Blind”
Technology transfer
Not quite the same
Yet, very similar
Text-entry
Screen Readers
VoiceOver
NavTouch
[Guerreiro, 2008]
User Evaluation
23 Participants
18 ~ 37 years old
Touchscreen experience
Texting experience
Apparatus
Text-entry Methods
QWERTY
VoiceOver
NavTouch
Visual Feedback
QWERTY
NavTouch
Mobility conditions
seated
corridor
navigation
Five word sentences
97% correlation
Measurements and Design
Words per Minute Error rate Minimum String Distance (MSD) Error Rate Preferred Walking speed
Text-entry speed
0
5
10
15
20
25
seated corridor navigation
Qwerty VoiceOver NavTouch
Text-entry speed
Text-entry sensitive to visually demanding conditions
AT were inefficient regarding speed
QWERTY the most sensitive (3.4 wpm)
Error Rate
0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
seated corridor navigation
Qwerty VoiceOver NavTouch
Error Rate
More deletions with QWERTY
Fewer errors with Assistive Technologies?
Quality of Text
0%
1%
2%
3%
4%
5%
6%
seated corridor navigation
Qwerty VoiceOver NavTouch
Quality of Text
NavTouch the most erroneous
Audio feedback improves quality of text
QWERTY the most sensitive
Walking Speed
0%
10%
20%
30%
40%
50%
60%
70%
80%
corridor navigation
Qwerty VoiceOver NavTouch
Walking Speed
Navigation course was more demanding
Users decreased walking speed
ATs were ineffective, possibly due to
cognitive load
Conclusion
Users reduce walking speed due to visual demand
QWERTY outperformed ATs
ATs are cognitively demanding
Audio is overlooked when
visual feedback is available
Future work
More visually demanding conditions 1-step selection methods No visual feedback Play with visual attributes
