Towards Mobile Touch Screen Inclusive User Interfaces: Differences and Similarities between Motor Impaired and Able-Bodied Users

Hugo Nicolau Tiago Guerreiro Daniel Gonçalves Joaquim Jorge

Mobile evolution

Tactile feedback

loss of tactile feedback

Loss of physical stability

hard to select targets

it occurs to everyone

… and motor impaired

some advantages

more pleasant

require less strength

Adapt to users’ needs

Provide the knowledge to build better touch interfaces

We performed …

Tested several …

Interaction Techniques

Screen areas …

… edges

Screen areas …

… middle

Screen areas …

1

2

3

4

5

… vertical distance

7 mm

… and target sizes

12 mm 17 mm

Tapping

Crossing

Directional Gesturing

15 participants 28-64 years old

C4-C7 lesion level 6 left-handed

never used touchscreens

18 participants 5 females, 13 males 20-45 years old

Results

Error Rate

X

Target Size

Motor Impaired

0%

10%

20%

30%

40%

50%

7mm 12mm 17mm

Gestures Tapping Crossing

Able-bodied

0%

5%

10%

15%

20%

25%

7mm 12mm 17mm

Gestures Tapping Crossing

Differences and Similarities

Tapping is the most similar Magnitude of errors Directional Gesturing

Middle

Motor Impaired

0%

10%

20%

30%

40%

50%

7mm 12mm 17mm

Gestures4Way Tapping Middle Crossing

Able-bodied

0%

2%

4%

6%

8%

10%

12%

14%

7mm 12mm 17mm

Gestures Middle Tapping Middle Crossing

Differences and Similarities

Similar performances with all techniques Differences are in the remaining of the screen

Edges

Motor Impaired

0%

20%

40%

60%

7mm 12mm 17mm

Tapping Middle Tapping Edge

0%

20%

40%

60%

Gesture Edge Gesture Middle

Able-bodied

0%

5%

10%

15%

20%

25%

30%

7mm 12mm 17mm

Tapping Middle Tapping Edge

Differences and Similarities

Edges do not provide additional support Tapping is hindered on edges

Vertical Distance

Motor Impaired

48% 31% 27%

43% 25% 28%

39% 28% 24%

40% 19% 15%

47% 19% 9%

7mm 12mm 17mm

Tapping

Able-bodied

10% 0% 0%

6% 2% 0%

8% 0% 0%

8% 1% 0%

38% 6% 0%

Tapping

7mm 12mm 17mm

Differences and Similarities

Tapping small targets, particularly near lower edge Reach restrictions

Towards Inclusive Design

Tapping is a suitable interaction technique

The one with more resemblances

Lowest error rates

12mm as a good compromise

Magnitude of errors

Much higher for motor impaired

0%

5%

10%

15%

20%

25%

30%

35%

40%

Gestures Tapping Crossing

5.6x 26x 6x

Able-bodied can easily perform Directional Gestures

Suitable alternative to Tapping (small targets) Motor impaired have many difficulties

Middle of the screen consistency

Similar performance with all interaction techniques

Remaining of the screen can

hinder or favor interaction

Reach restrictions

Upper edge targets are harder to acquire for M.I. For A.B. small targets near bottom edge are harder

Instantiate our findings Investigate situational impairments

Future Work

THE END.

Hugo Nicolau hman@vimmi.inesc-id.pt