Duration discrimination by rats.

A psychophysical procedure was used to determine the difference limen for the duration of a signal that ranged from .5 to 8.0 sec. The accuracy of three rats in keeping track of the duration was assumed to be limited by three factors: (a) inattention to the signal on some trials, (b) variability in starting to time the duration when the signal begins (and/or in stopping to time the duration when the signal ends), and (c) factors related to signal duration itself. A generalized Weber model provided a better approximation to the growth in the difference limen as a function of signal than a generalized Counter model.