Processing of Empty and Filled Time Intervals in Pigeons

Douglas S. Grant and Diane C. Talarico

University of Alberta

Pigeons were trained initially with 2- and 8-s empty or filled intervals as sample stimuli. Interval onset and termination was signaled by 1-s start and stop markers. Following retention and psychophysical testing, both groups were trained with the alternative type of interval and the tests were repeated. Group empty-first demonstrated a choose-long effect with both empty and filled intervals. Group filled-first demonstrated a weak (and nonsignificant) choose-short effect with filled intervals, and a robust choose-long effect with empty intervals. Both groups tended to time the markers, and to add that duration to the sample duration, only on filled-interval trials. Initial training with empty intervals alters the way pigeons process temporal information on filled-interval trials, whereas initial training with filled intervals has little effect on the processing of temporal information on empty-interval trials.