MEMORY CODES FOR TEMPORAL AND NONTEMPORAL SAMPLES IN MANY-TO-ONE MATCHING BY PIGEONS

Pigeons were trained to match temporal (2 and 8 sec of keylight) and c olor (red and green) samples to vertical and horizontal comparison sti muli. In Experiment 1, samples that were associated with the same corr ect comparison stimulus displayed similar retention functions, and the re was no significant choose-short effect following temporal samples. This finding was replicated in Phase 1 of Experiment 2 for birds maint ained on the many-to-one mapping, and it was also obtained in birds th at had been switched to a one-to-one mapping by changing the compariso n stimuli following color samples. However, in Phase 2 of Experiment 2 , when the one-to-one mapping was produced by changing the comparison stimuli following temporal samples, a significant choose-short effect was observed. In Experiment 3, intratrial interference tests gave evid ence of temporal summation effects when either temporal presamples or color presamples preceded temporal targets. This occurred even though these interference tests followed delay tests that failed to reveal si gnificant choose-short effects. The absence of significant choose-shor t effects in Experiment 1 and in Phase 1 of Experiment 2 indicates tha t temporal samples are not retrospectively and analogically coded when temporal and nontemporal samples are mapped onto the same set of comp arisons. The interference test results suggest that the temporal summa tion effect arises from nonmemorial properties of the timing system an d is independent of the memory code being used.