| Abstract: | Pigeons were trained in a within-subjects design to discriminate empty intervals (bound by two 1-sec visual markers) and filled
intervals (a continuous visual signal). The intervals were signaled by different visual stimuli and they required responses
to different sets of comparison stimuli. In Experiment 1, empty intervals were judged longer than filled intervals. The difference
between the point of subjective equality (PSE) for the empty intervals and the PSE for filled intervals increased as the magnitude
of the anchor-duration pairs increased. Although there was more pecking during filled intervals than during empty intervals,
there was no significant correlation between pecking during filled intervals and the value of the PSE. In Experiment 2, empty
intervals continued to be judged longer than filled intervals, even when pigeons were required to refrain from pecking during
filled intervals. Keypecking per se does not appear to play an important role in the empty-filled timing difference. |
