Monday, March 10, 2008

Inspiration: Dwell-Based Pointing in Applications (Muller-Tomfelde, 2007)

While researching the optimal default value for dwell time execution I stumbled upon this paper by Christian Muller-Tomfelde at the CSIRO ICT Centre, Australia. It does not concern dwell time in the aspect of gaze based interaction but instead focuses on how we handle dwell times while pointing towards objects and conveying this reference to a communication partner. How long can this information be withheld before the interaction becomes unnatural?

"This paper describes exploratory studies and a formal experiment that investigate a particular temporal aspect of human pointing actions. Humans can express their intentions and refer to an external entity by pointing at distant objects with their fingers or a tool. The focus of this research is on the dwell time, the time span that people remain nearly motionless during pointing at objects. We address two questions: Is there a common or natural dwell time in human pointing actions? What implications does this have for Human Computer Interaction? Especially in virtual environments, feedback about the referred object is usually provided to the user to confirm actions such as object selection. A literature review and two studies led to a formal experiment in a hand-immersive virtual environment in search for an appropriate feedback delay time for dwell-based pointing actions. The results and implications for applications for Human Computer Interaction are discussed. "

I find the part about the visual feedback experiment interesting.

"We want to test whether a variation of the delay of an explicit visual feedback for a pointing action has an effect of the perception of the interaction process. First, feedback delay time above approximately 430 ms is experienced by users to happen late. Second, for a feedback delay time above approximately 430 ms users experience waiting for feedback to happen and third, feedback delay below 430 ms is considered by users to be natural as in real life conversations. "

Questions asked:
  • 1: Do you have the impression that the system feedback happened in a reasonable time according to your action? Answer: confirmation occurred too fast (1), too late (7).
  • 2: Did you have the feeling to wait for the feedback to happen? Answer: no I didn’t have to wait (1), yes, I waited (7).

  • 3: Did you have the impression that the time delay for the feedback was natural? (i.e., as in a real life communication situation) Answer: time delay is not natural (1), quite natural (7).

"This allows us to recommend a feedback delay time for manual pointing actions of approximately 350 to 600 ms as a starting point for the development of interactive applications. We have shown that this feedback delay is experienced by users as natural and convenient and that the majority of observers of pointing actions gave feedback within a similar time span."

No comments: