We report a new type of perceptual assimilation related to time perception. In many sensory dimensions, it has been observed that, when some objects or events are spatially and temporally close together, characteristics of these events can approach one another (e.g., Brown & Mueller, 1965; Helson, 1963). This phenomenon is called assimilation.

...assimilation appeared also in speech perception (e.g., Repp, 1978; Shigeno & Fujisaki, 1979). It is often thought that these assimilations take place when a single continuous dimension is mapped into perceptual categories (e.g., rhythmic and phonemic categories) and does not occur directly with regard to the dimension constituting the stimulus pattern.