4. Discussion In the field of experimental psychology, time perception refers to the time interval that is estimated by one's own perception. Numerous studies have been conducted in this field, and several models have been constructed and proposed on the basis of the experimental results. For example, in the change model, a participant's internal clock changes depending on their metabolism (Hoagland, 1933, 1981); in the storage size model, perceived time changes depending on the amount of information stored in the participant's memory (Ornstein, 1969); and in the attention model, perceived time changes depending on the attention distribution for the time and the non-time information processing systems (Thomas and Canter, 1975, 1976; Thomas and Weaver, 1975). There is also the four multiplicative factor model (Matsuda, 1996), which is given by equation (2); this model is an integration of the aforementioned models. In this model, the duration of perceived time (T) can be expressed by multiplying 1) elapsed time (t) with 2) the frequency of the tempo of the internal clock (f), 3).