Study on the Relationship between Usability and Number of Buttons of an Interface Console
Michio Miyakawa, Nozomu Koyama, Yoshinobu Maeda · IEEJ Transactions on Electronics Information and Systems · 2009
Usability, or easiness of operation of a console such as a universal remote console (URC), has been investigated in terms of the optimum number of buttons of the console which minimizes the operation time. The console operation is consisted of two major processes, that is, cognition of the button and motion of hand to press it. Cognitive workload would increase in accordance with the increase in number of buttons because difficulty in finding a correct button is increased. Conversely, physical workload would increase when number of buttons is decreased, because one has to press many times the same buttons in different meanings. Thus the optimum number of buttons which minimizes the total operation time of a console appears. To verify this hypothesis, several virtual consoles equipped with different number of buttons were developed on a PC. Subjects were asked to input designated family names in Roman alphabets. Easiness of operation, i.e. usability was evaluated by the operation time among 49 subjects. The operation time showed the minimum value when the number of buttons was approximately 18.