Monday, March 1, 2010

An empirical evaluation of touch and tangible interfaces for tabletop displays

Authors:
Aurlien Lucchi
Patrick Jermann
Guillaume Zufferey
Pierre Dillenbourg

Discussion:
Goal: Evaluation of touch and tangible interfaces on table top displays.
This is a comprehensive user study with 40 users and a set of activities to compare touch and tangible interfaces. Tangible interfaces are complex to measure based on Fitt's law. A top projected table top system is built for supporting both the interfaces. The table can track multiple finger interaction. The system uses a camera mounted on the top of the table to track the tagged tangible objects. The toolbar in the touch interface was replaced by the tangible objects. Users were asked to model a building using shelves and walls. The virtual wall in touch interface was rescalable while the tangible one was not. Activities like translation and rotation has natural gestures in tangible. Selection did not have any meaning in the tangible interface. Addition, removal and adjustment activities were performed physically in tangible interface while certain tool bar icons were used in touch interface. An introductory video was presented to the users to explain the different actions available. The actiions of the users were video taped and logged. The user were asked to model a warehouse. To compare the interfaces 3 variables were used - Completion time of overall experiment, completion time of each action and Accuracy. Overall completion time favored tangible interfaces. Comparing individual activities showed that scaling, translation and deletion operations favor touch interface while addition operation favors tangible interface. Touch was slightly less accurate. User preferences show that tangible interfaces were easier to learn than touch interfaces. Touch interface made user more stressed and irritated.

Summary:
Tangible interface seem to be more intuitive way to interact. But the rigidity involved or the difficulty involved in editing may affect the user experience. I am impressed by the user study. It is expensive, systematic and has both quantative and qualitative data.
It would have been interesting if the authors did an follow up study to see if the users retained what they learned.

Comments:

3 comments:

  1. The user study was certainly very thorough. It is a little unfair to compare the two as we have had our whole lives to practice with tangible interfaces from our first set of building blocks, whereas by comparison we have very little experience with touch interfaces.

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  2. I agree, while tangible interfaces are more intuitive, it does not necessarily mean they are more efficient.

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  3. I liked the user study as well. It was detailed, unlike certain others we've read. Anyways, ditto on the intuitive stuff. As always, it depends on the implementation.

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