DELAYED MATCHING-TO-SUCCESSIVE-SAMPLES IN PIGEONS - SHORT-TERM-MEMORYFOR ITEM AND ORDER INFORMATION

Short-term memory for order information in pigeons was explored by usi ng a delayed matching-to-successive-samples task (DMTSS). Experiment 1 indicated that pigeons can accurately report the order of two success ively presented samples. Experiments 2, 3 and 4 specifically addressed the representation of order information in short-term memory. Experim ent 2 showed that when the duration of the first sample (Sl) was very long, or when the duration of the second sample (S2) was very short, o rder errors increased relative to baseline (Sl and S2 of equal duratio n), suggesting that memory strength plays an important role in the dis crimination of order. The possibility that strength information is nec essary for accurate DMTSS performance was tested in Experiments 3 and 4. Pigeons continued to match accurately when memory strength and orde r were uncorrelated.