Racel Williams

Fitt’s Law2012


A fun game that puts Fitt’s Law to the test. From the equation, we see a speed–accuracy trade off associated with pointing, whereby targets that are smaller and/or further away require more time to acquire.

Contribution: I was a team member and lead developer on this project. Using Flash and Actionscript 3, we created a game that logged reaction time, clicks, errors, and magnitudes to test the validity of Fitt's Law.
Process: Each of our 6 group members participated in 6 trials consisting of 150 balloons each. The balloons varied in size, shape, and distance from each in order to test out Fitt's Law. Each participant utilized the same computer to ensure consistency across trials. The study was a within-participants design that utilized the Latin Square to avoid ordering and carryover effects. After each trial, users were given a rest period of 2 minutes.
Our results did indicate an increase in difficulty would increase reaction time, but we did get surprising result of negative index of difficulties. We discovered that Fitt's Law does not do well with small index of difficulties and we then modified our calculations to align with the Shannon Formulation. This solved the negative index of difficulty, but in addition some of the data we collected had to be eliminated from our set as it indicated values that were less than 300ms indicating that the reactions by the participants did not require cognition.
Play the Fitt's Law !Game