The Effect of Inclination on the Perceived Usability of Washing Machine Interfaces

Usability is significantly influenced by the perceptual characteristics of interfaces. This study investigates the effect of the
inclination of elements in a physical interface on the evaluation of perceived usability. In the first experiment, a psychophysical
methodology was employed to measure the perceived usability of 15 different washing machine interfaces. A model of perceived usability was adopted, which incorporates four factors: understandability, easeof use, safety, and attractiveness. The results indicate that participants were able to discriminate between the stimuli based on the factors considered. In the second experiment, the inclinations of the interface elements (buttons, LEDs, icons and text labels) were systematically modified. The findings reveal that inclination significantly affects three perceived usability subcomponents: understandability, ease of use, and attractiveness.