In roving-referent bisection, three duration values are presented sequentially on each trial, two referents and then a probe, and the observer is instructed to indicate whether the probe is more similar to the duration of the first or second trial referent. Data from three experiments are reported which consistently indicate that human observers do not compare the probe to the trial referents in roving-referent bisection. Rather, they base their judgment on the absolute value of the probe rather than on its relationship to the trial referents. The data are consistent with Gibbon's (1981) formulation of the decision process in bisection which specifies that the probe is compared to a criterion duration value. Although many studies have used bisection to study temporal memory, the data from the present experiments suggest that referent memory is not a dominant source of variability in human temporal bisection.