Effects of variable durations of food availability on interval time-place learning with pigeons Columba Livia.

We assessed the effects of variable durations of food availability on an interval time-place learning task. 3 pigeons were exposed to a task in which food could be obtained for responses in one of four feeders according to an RI 25 s during 3 min, after which, food could be obtained on a different feeder according to the same schedule. The correct feeder changed following a fixed sequence that was repeated four times throughout the session. After 50 training sessions, an Open Hopper Test was conducted, after which, the second training condition ensued. This condition was like the first one with the exception that the availability period could be either 1,2,3, or 6 min long. A second test was conducted after 50 sessions of this training. Another group of 3 birds experienced these conditions in the reverse order. Data suggest that birds solved the task via interval timing under the fixed duration condition, and via ordinal timing when faced with variable durations. Birds learned the fixed sequence involved in the task under both conditions. Although the present data agree with previous research exploring variability in TPL tasks, they do not necessarily support previous claims for an asymmetrical role of spatial and temporal information in these tasks.

Evidence of non-circadian timing in a low response-cost daily Time-Place Learning task with pigeons Columba Livia.

Previous research has shown that rats require high response cost in order to display circadian timing in daily Time-Place Learning (TPL) tasks. For many possible reasons, no explicit effort to explore the effects of response cost on the performance of other species in these tasks has been made. Therefore, the present paper explores the effects of response cost on pigeon's performance on a daily TPL task. Head entry responses were reinforced according to a Random Interval schedule of reinforcement on one feeder during morning sessions and on another feeder during afternoon sessions. Feeders were located 8 cm apart for one group of birds (Group Near) and 56 cm apart for another group (Group Far). After 50 training sessions, testing began. Test sessions consisted of skipping either the morning or the afternoon session. Results show that most birds in the near group respond primarily on the opposite feeder during the first 20 s of the test sessions and then they switch to the correct feeder. On the other hand, most birds in Group Far respond at the same rate on both opposite and correct feeders during 20 s, and then they respond primarily on the correct feeder. The possibility of these data revealing non circadian timing for birds in a low response-cost daily TPL task is discussed along with the implications of such a finding for previous literature that claims that this type of performance could be unique to rats.