On the Limits of the Human Motor Control Precision: The Search for a Device's Human Resolution

Input devices are often evaluated in terms of their throughput, as measured by Fitts' Law, and by their resolution. However, little effort has been made to understand the limit of resolution that is controllable or "usable" by the human using the device. What is the point of a 5000 dpi computer mouse if the human motor control system is far from being able to achieve this level of precision? This paper introduces the concept of a Device's Human Resolution (DHR): the smallest target size that users can acquire with an ordinary amount of effort using one particular device. We report on our attempt to find the DHR through a target acquisition experiment involving very small target sizes. Three devices were tested: a gaming mouse (5700 dpi), a PHANTOM (450 dpi), and a free-space device (85 dpi). The results indicate a decrease in target acquisition performance that is not predicted by Fitts' Law when target sizes become smaller than certain levels. In addition, the experiment shows that the actual achievable resolution varies greatly depending on the input device used, hence the need to include the "device" in the definition of DHR.

[1]  Yves Guiard,et al.  Navigation as multiscale pointing: extending Fitts' model to very high precision tasks , 1999, CHI '99.

[2]  P. Fitts.  The information capacity of the human motor system in controlling the amplitude of movement. , 1954, Journal of experimental psychology.

[3]  Allen Newell,et al.  The psychology of human-computer interaction , 1983 .

[4]  Martin R. Gibbs,et al.  Mediating intimacy: designing technologies to support strong-tie relationships , 2005, CHI.

[5]  Ka-Ping Yee,et al.  Peephole displays: pen interaction on spatially aware handheld computers , 2003, CHI '03.

[6]  Marco Winckler,et al.  Human-Computer Interaction - INTERACT 2009, 12th IFIP TC 13 International Conference, Uppsala, Sweden, August 24-28, 2009, Proceedings, Part I , 2009, INTERACT.

[7]  Jeremy R. Cooperstock,et al.  Did "Minority Report" Get It Wrong? Superiority of the Mouse over 3D Input Devices in a 3D Placement Task , 2009, INTERACT.

[8]  ZhaiShumin.  Characterizing computer input with Fitts' law parameters , 2004 .

[9]  I. Scott MacKenzie,et al.  Accuracy measures for evaluating computer pointing devices , 2001, CHI.

[10]  Renaud Blanch,et al.  Semantic pointing: improving target acquisition with control-display ratio adaptation , 2004, CHI.

[11]  Patrick Baudisch,et al.  Precise selection techniques for multi-touch screens , 2006, CHI.

[12]  Shumin Zhai,et al.  Characterizing computer input with Fitts' law parameters-the information and non-information aspects of pointing , 2004, Int. J. Hum. Comput. Stud..

[13]  Shumin Zhai,et al.  High precision touch screen interaction , 2003, CHI '03.

[14]  I. Scott MacKenzie,et al.  Performance differences in the fingers, wrist, and forearm in computer input control , 1997, CHI.

[15]  Shumin Zhai,et al.  The influence of muscle groups on performance of multiple degree-of-freedom input , 1996, CHI.

[16]  Yves Guiard,et al.  Preface: Fitts' law 50 years later: Applications and contributions from human-computer interaction , 2004 .

[17]  I.,et al.  Fitts' Law as a Research and Design Tool in Human-Computer Interaction , 1992, Hum. Comput. Interact..

[18]  Daniel Vogel,et al.  The Impact of Control-Display Gain on User Performance in Pointing Tasks , 2008, Hum. Comput. Interact..

[19]  Frank R. Abate,et al.  The new Oxford American dictionary , 2001 .

[20]  Patrick Baudisch,et al.  Back-of-device interaction allows creating very small touch devices , 2009, CHI.

[21]  Daniel Vogel,et al.  Shift: a technique for operating pen-based interfaces using touch , 2007, CHI.