Gaze-controlled HCI and the Midas-Touch problem

Hendrik Koesling

Collaborative Research Centre 673 Alignment in Communication

Centre of Excellence 277 Cognitive Interaction Technology

Bielefeld University

Introduction

“Gaze mouse”

Gaze-controlled HCI: Issues …

How to select an action?

How to detect the intention to select an action?

Midas-Touch problem

Distinction between attention for exploration and attention for selection

… and solutions

Volitional action-selection methods

Gaze mouse + manual action selection

Fixating

Blinking

Separate action-selection areas

… and solutions

Volitional action-selection methods

Gaze mouse + manual action selection

Fixating

Blinking

Separate action-selection areas

Research Questions

Efficiency: Is one of the fixation or blinking methods more efficient than the other?

Usability: Do users prefer one method to the other?

Acquisition: How easy are the two methods to learn?

Experimental method

Task

Gaze typing

Participants

20 German native speakers

10 female, 10 male; mean age 24.3 years

Apparatus

LC Technologies EyeGaze eye tracker @ 120 Hz

t

Experimental method

Stimuli & Procedure

Task area

Input control area

Interaction area

German sentences

6-11 words, 55-65 characters

Selection threshold: 300 ms

…

…

+MB

Experimental method

Design

2 blocks (fixation, blinking)

5 trials per block

Balanced for number of characters,sequence of methods & gender

+ Questionnaire

IV: Method, gender, seq. of methods

DV: Error rate, completion time; quest.

Results – Error rate ER

Fewer errors with blinking method

t(19) = 4.187; p < 0.001

Females: t(9) = 2.480; p = 0.038Males: t(9) = 3.279; p < 0.001Females vs. males: not signif.

No gender difference

Blink-fix: t(9) = 2.124; p = 0.063 (trend)Fix-blink: t(9) = 4.351; p < 0.001

Without practice, blinking & fixation equalPractice benefit for blinking method

Results – Completion time CT

Not signif.

No difference in CT between methods

Females: not signif.Males: not signif.Females vs. males: t(9) = 2.232; p < 0.031

Females’ CTs longer than males’Practice benefit for fixation method

Blink-fix: t(9) = 4.507; p < 0.001Fix-blink: not signif.

Results – Practice Usability

Initial improvement through practice

Followed by possible fatigue effects

User ratings

Method easier to get used to?

… less error prone?

… more accurate?

… less tiring?

… more intuitive?

Use gaze-controlled HCI?

Conclusions

Both gaze-contingent selection methods present feasible approaches to solve the Midas-touch problem.

No method can be preferred over the other.

Blinking method produces fewer errors and allows for more accurate selections

Without practice, fixation method may not necessarily be more error-prone. Task completion times in particular for the fixation method benefit from practice.

Thus, after practice, fixation method may be more efficient than blinking method.

Furthermore, fixation method is rated as less tiring and more intuitive – relevant with regard to user-friendliness, user satisfaction and possible long-term effects of novel interaction methods on users.

Conclusions

Blinking method appears to be well suited for applications where only few selections are needed, that does not rely on a “fluent” input stream and does not allow much time for practice.

Possible applications: ticket vending machines, filling in forms in multiple choice style, sending action command to robots.

Fixation method better suited for continuous, long-lasting and rapid interaction with an application. When users are appropriately trained in using the fixation method, they may consider this interaction method an intuitive, user-friendly means of communication with their environment.

Possible applications: virtual keyboards, in particular for users with motor control deficits.

Outlook

Test handicapped participants

Examine practice effects more closely

Evaluate alternative gaze-controlled action-selection methods

…

Thank you!