Paper Reading #29- Usable gestures for blind people: understanding preference and performance

Title: Usable gestures for blind people: understanding preference and performance
Reference Information:
Shaun Kane, Jacob Wobbrock, and Richard Ladner, "Usable gestures for blind people: understanding preference and performance". CHI '11 Proceedings of the 2011 annual conference on Human factors in computing systems. ACM New York, NY, USA. ©2011. ISBN: 978-1-4503-0228-9.
Author Bios:
Shaun Kane- I am an assistant professor in the Department of Information Systems at the University of Maryland, Baltimore County. My primary research interests are accessible user interfaces and mobile human-computer interaction. My work explores ways to make mobile devices easier to use, especially for people with disabilities and people in distracting environments.
Jacob Wobbrock- I am an Associate Professor in the Information School and an Adjunct Associate Professor in the Department of Computer Science and Engineering at the University of Washington.
Richard Ladner- Boeing Professor in Computer Science and Engineering in the Department of Computer Science and Engineering, the University of Washington.
Summary:

• Hypothesis: If designers can better understand how blind people interact with a touch-screen device as opposed to people with sight, then products can be better suited and accommodated for blind people.
• Methods: The authors conducted two studies to better understand the contrast between blind people and sighted people in terms of interactions with a touch-surface device. In the first, the authors asked 10 blind people and 10 sighted people to invent gestures to complete a task on a tablet PC. In the second, the authors asked the same participants to perform reference gestures to perform the tasks.
• Results: From the first study, the participants each created 2 possible gestures for each task. They ended up rating their grstures based on "easyness" and "good match". There were no significant differences between the blind and the sighted here. A count revealed that the blind people's gestures contained a significantly higher gesture count than the sighted people's. Also, the blind people tended to make more abstract gestures for tasks whereas sighted people made more symbolic gestures. For the second study, some blind participants either opted to skip some gestures because of unfamiliararity or the results were discarded because they were not accurate whatsoever. Of the gestures performed, blind people and sighted people typically rated the "goodness" of the gestures around 5.7 of 10. The authors found that blind people tended to create larger areas or shapes for their gestures than sighted people. The size deviation also indicated that the variation of size was much greater with blind people than with sighted people. The authors found that the blind people took almost twice as long to complete the tasks on average as the sighted people. Blind people had generally a greater inaccuracy with locating specific spots on the screen than sighted people. It was also noted that blind people's gestures were not as smooth or fluid as sighted people's.
• Content: The study that the authors conducted found that blind people prefer gestures involving the areas on the screen closer to the edges and that require multiple touches to complete. The authors also uncovered significant performance differences between gestures performed by the blind vs the sighted (noted above). The authors concluded with several notes for future designers: "avoid symbols used in print writing, favor edges, corners, and other landmarks, reduce demand for location accuracy, and limit time-based gesture processing".

Discussion:
I think this paper was really interesting. This becomes a real issue when a company shows that they are taking interest in incorporating as large of a population as possible and not punishing the blind for not being able to use one of their products. This is definitely one applicatory situation for the motivation behind this paper. The authors, in my mind, deifnitely achieved their goals by allowing future designers for touch-surface devices to see the differences between sighted and blind people's interactions. Some things need to be taken into account when designing new products that you wish to incorporate the blind (noted above). Some of the things, such as accuracy of the gestures being less for the blind, seemed really obvious to me and simply studying that could have been a little waste of time. But I guess in order to know for sure, it had to be studied. I would love to see a finished prototype of a device using these princicples in future work.