The impact of keyboard layouts on dwell-free eye-driven typing performance

Abstract

The modern technique of dwell-free eye typing enables more efficient communication than the conventional, dwell-based technique. Nevertheless, speech and motor impaired individuals, who are also digital immigrants, may experience challenges with this technique due to their unfamiliarity with keyboard layouts. Whereas studies evaluated the performance of different keyboard layouts with dwell-based eye typing and physical keyboards, their findings cannot be generalised for dwellfree eye typing since this technique is characterised by fundamental interaction differences. The purpose of this study is to provide speech and occupational therapists with insights on keyboard recommendations based on the users’ aptitudes for and experience with technology. This study considers three standard keyboards; QWERTY, Dvorak and the alphabetical layout, in light of deriving an optimised keyboard for users with limited typing experience. Twenty digital immigrants used all three keyboards during 45-minute experiment sessions. Results emerging from this study informed the design of a new layout (DF-AJR) which mitigates observed shortcomings in standard layouts for dwell-free eye-typing. Results showed that QWERTY offered the best performance for digital immigrants when using dwell-free eye typing (this was ascribed to their previous experience with this layout), followed by the alphabetical and Dvorak keyboards respectively. However, participants who had less than one year’s experience in using a keyboard showed similar performance with the QWERTY and alphabetical layouts, suggesting that the QWERTY layout may not yet be clearly imprinted in the minds of this group of users. This introduced the opportunity for an alternative keyboard layout, designed for users who lack experience with QWERTY. Whereas previous studies, which used alternative modes of input, concluded that Dvorak has the potential to outperform QWERTY, this was not observed with dwell-free eye typing. Observed shortcomings for standard layouts were mitigated in the redesigned keyboard, DF-AJR, which utilised the English-letter frequency list and adopted an alphabetical bias. Initial results show that the participants’ performance improved with the DF-AJR keyboard and was also preferred by participants. Moreover, while introducing dwell-free eye typing over the web, the optimised client-side web-based tool developed in this study reduces the financial burden associated with acquiring eye-driven AAC devices.