The main contribution of this paper is establishing the method to enhance work efficiency unconsciously by controlling the time rate that a virtual clock shows. Recently, it has been revealed that work efficiency is influenced by various environmental factors such as work environment's atmosphere, temperature and so on. On the contrary, it has become clear that the work rate is affected by a time sensation. While working, the more amount of information we process in a limited time, the longer elapsed time we perceive. Besides, the higher cognitive load we get from difficult works, the longer elapsed time we perceive. In this way, a perception of time rate and a cognitive load of works affect each other. In this study, we focus on a "clock" as a tool, which gives the recognition of time rate and length for everyone mutually. We propose a method to improve a person's work efficiency, especially work rate unconsciously by giving an illusion of false sense of the passaged time by a virtual clock that displays the time rate that differ from real one visually. We conducted experiments to investigate the influence of the changes in the displayed virtual time rate on time perception and work efficiency. Besides, to evaluate an effect of an implication of a "clock", we conducted the counter experiments with a flicker stimulus and a reversely rotated virtual clock. The experimental results showed that by displaying the accelerated time rate, it is possible to improve work efficiency with constant time perception, and a "clock" is critical for enhancing work rate.
