The effect of marker size on the perception of an empty interval.

Research shows that the time that is spent perceiving a brief visual stimulus is experienced as increasing as the size of the stimulus increases. We examined whether the experienced duration of time that is spent attending the perception of an empty interval--demarcated by the offset of one marker and the onset of a second marker--depends on the size of the markers themselves. Previous theories predict that the perceived time that is spent viewing offset-to-onset intervals decreases as the size of the markers increases, and that the perceived time that is spent viewing the markers increases. We demonstrated that empty intervals between the presentations of large markers were perceived to be longer in duration than those occurring between the presentations of small markers, and that the second marker was critical to this effect of physical size on apparent duration. We report that the size effect disappeared when the interval was filled with the presentation of a circle, and we conclude that the intensity of the second marker altered perceptions in an empty-interval-specific manner.