Interaction Space of Chords on a Vertical Multi-touch Screen

Despite the increasing use of Multi-Touch (MT) capable devices, novel interaction techniques need to be examined in order to swift from a single-touch WIMP interaction paradigm to a MT one.In this work, we focus on chord interaction on vertical MT screens. Chord is the simultaneous touch of more than one finger on the MT screen. Based on a user experiment with 12 users, we explore the positioning - interaction space of the chord technique, by investigating a relation among the type of the chord (number of fingers) and the position on the screen that the chord was applied. The empirical results have indicated an interaction pattern that demonstrates a significant relation between the type of the chord that was applied (number of fingers) and its position on the screen. Our results show that as the number of fingers needed for a chord increases, the nearer from the bottom left of the screen this chord is to be applied. Notably, our results give evidence of the fact that there is a threshold (five-finger-chord) beyond which the above relation is not strong.