Eve Hoggan, Stephen Brewster & Jody Johnston
Investigating the Effectiveness of Tactile Feedback for Mobile
Touchscreens
TopicsMobile touchscreen displays
Tactile feedback for fingertip interaction
Physical keyboards versus tactile touchscreen keyboards
Can high-spec virtual tactile feedback improve the usability of touchscreen keyboards further?
Dynamic mobile environments
Dynamic mobile environments
Dynamic mobile environments
Dynamic mobile environments
Touchscreens no longer need physical keyboards
Fingertip interaction
Touchscreen buttons cannot provide the natural haptic response that physical buttons can when touched
Mobile touchscreens
Feel the buttonsUsers can physically ʻfeelʼ the touchscreen interface
Haptic feedback: applying forces, vibrations or motion to the fingertip
We studied the effects of adding tactile feedback to a touchscreen mobile QWERTY keyboard
Tactile featuresFingertip-down and click events
Home keys
Fingertip-slip
Physical QWERY keyboard
Palm Treo 750
Comparison
Physical QWERY keyboard
Palm Treo 750
Comparison
Touchscreen keyboard
Samsung i718
Built in Immersion “Vibetonz” actuator
With and without tactile feedback conditions
MethodParticipants were shown a phrase and asked to memorise it, then type itErrors, keystrokes per character, time and workload were measuredLocations: lab and mobile (on a train)
Train environment
Noise, light, movement and vibration levels are very dynamic
Train environment
Noise, light, movement and vibration levels are very dynamic
Accuracy
Physical keyboard and tactile touchscreen performed best
Physical keyboard Standard touchscreen Tactile touchscreen
Accuracy
Physical keyboard and tactile touchscreen performed best
Lab Mobile0
10
20
30
40
50
60
70
80
90
100
Ave
rage
% p
hras
es e
nter
ed c
orre
ctly
Physical keyboard Standard touchscreen Tactile touchscreen
Accuracy
Physical keyboard and tactile touchscreen performed best
Lab Mobile0
10
20
30
40
50
60
70
80
90
100
Ave
rage
% p
hras
es e
nter
ed c
orre
ctly
Physical keyboard Standard touchscreen Tactile touchscreen
Accuracy
Physical keyboard and tactile touchscreen performed best
Lab Mobile0
10
20
30
40
50
60
70
80
90
100
Ave
rage
% p
hras
es e
nter
ed c
orre
ctly
Physical keyboard Standard touchscreen Tactile touchscreen
Keystrokes per character (KSPC)
Significantly more KSPC on tactile touchscreen
00.20.40.60.81.01.21.41.61.82.0
Lab Mobile
Ave
rage
KSP
C
Physical keyboard Standard touchscreen Tactile touchscreen
Time per phrase
Standard touchscreen slower than others
0
3.5
7.0
10.5
14.0
17.5
21.0
24.5
28.0
31.5
35.0
Lab Mobile
Ave
rage
tim
e pe
r ph
rase
(se
cs)
Physical keyboard Standard touchscreen Tactile touchscreen
Additional experiment
Specialised actuators Simple spatial location
AccuracyThe number of phrases entered correctly on the physical keyboard, tactile touchscreen and PDA with specialist actuator are very similar with no significant difference 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Lab Mobile
Ave
rage
phr
ases
ent
ered
cor
rect
ly
Physical keyboard Standard touchscreen Tactile touchscreenPDA with dual C2 actuators
KSPC
Users corrected significantly more errors on the tactile touchscreen
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Lab Mobile
Ave
rage
KSP
C
Physical keyboard Standard touchscreen Tactile touchscreenPDA with dual C2 actuators
SpeedUsers typed significantly faster on the physical keyboard and PDA with specialist actuators
0
5
10
15
20
25
30
35
Lab Mobile
Ave
rage
tim
e pe
r ph
rase
(se
cs)
Physical keyboard Standard touchscreen Tactile touchscreenPDA with dual C2 actuators
Workload
Levels of annoyance were highest on the PDA with specialist actuators
Perceived performance decreased and all other measures increased when using the standard touchscreen
Future workFingertip interaction with other types of traditional widgets
Novel tactile widgets, e.g. T-Bars (Hoggan et. al, MobileHCI 08)
Alternative mobile environments
Initial audio and crossmodal results
Audio feedback is as good as tactile in the lab but not on the train
Crossmodal feedback produces levels similar to tactile
ConclusionThe addition of tactile feedback significantly improved finger-based text entry
High-spec tactile actuators improve typing speeds even further
The benefits of touchscreen displays do not have to come at the cost of poorer text entry, we can regain some of the natural feeling lost
Thank youEve Hoggan & Stephen Brewster
{eve, stephen}@dcs.gla.ac.uk
www.tactons.org
Many thanks to Nokia, Immersion and SPT
iPhone version can be downloaded at iphone-haptics.googlecode.com