Applying Fitts’ Law in a Mobile and Pervasive Computing Environment

The computing environment of the future will be mobile and pervasive, involving a paradigm shift away from the desktop. Inspired by the beginnings of this shift, from desktop to mobile and pervasive computing, this project set out to look at whether mobile and pervasive computers were different to desktop computers. Specifically, its original aim was to investigate the practice of simply scaling the desktop interface up or down in order to implement if on large and small screen computers respectively. This investigation gave rise to the uncovering of a possible flaw in Fitts’ Law, the model intended for use in the comparison between mobile, pervasive and desktop computers. Following these two lines of investigation, it was found that small and large screens are significantly different from the medium, desktop screen and that Fitts’ Law is scale independent while the pointing task it models is not. This leads us to the conclusion that the Windows graphical user interface should not be shrunk to fit on to small screen displays or stretched to fill a large screen. We also conclude that although Fitts’ law has served as an accurate model in Human Computer Interaction, it has been faulty since its first application in the area. In a mobile and pervasive environment the problem of scale independence becomes more apparent and greatly reduces the predictive and descriptive powers of Fitts’ Law.