Picture superiority effect in authentication systems for the blind and visually impaired on a smartphone platform

Pictures are more likely to be remembered than words or text. For smartphone authentication, graphical password interfaces employing both visual objects and auditory cues are more memorable than textual password interfaces among sighted people because the graphical interface evokes visual imagery in the brain. However, interfaces employing visual imagery have not been studied for the blind and visually impaired. The objective of this research is to demonstrate that graphical password interfaces, designed to evoke visual imagery among blind and visually impaired users, improve the ease of use of smartphone authentication systems. We developed and tested two graphical password systems, BlindLoginV2, which employs object picture superiority effect and AudioBlindLogin, which employs auditory cues to enrich the picture superiority effect. We collected quantitative metrics measuring login speed, configuration time and failure rates immediately after training, 1 h later, 1 day later and 1 week later and qualitative evidence through face-to-face interviews. This study shows that blind and visually impaired users benefit from the picture superiority effect and passwords are more memorable, quicker to key in with greater accuracy as compared to 4-character textual password interfaces. Using the authentication system as an example, we demonstrate that visual imagery can be evoked in blind and visually impaired users through careful design of smartphone interfaces and when paired with additional sensory cues such as audio, can significantly improve the ease-of-use and thereby enhance access among visually impaired users to the rich array of security features available in smartphones.