Interocular transfer of learning in the pigeon: visuo-motor integration and separation of discriminanda and manipulanda.

Interocular transfer (IOT) of visual information in pigeons has been shown to vary according to the training paradigm. In the present experiment 6 groups of pigeons were trained on a color discrimination using 6 different training paradigms. It was found that a successive discrimination with a single key and a simultaneous discrimination with either two keys arranged horizontally or with two keys arranged vertically, all produced successful interocular transfer of learning. On the other hand, the other 3 training paradigms, in which the discriminative stimulus was presented on 'stimulus key' and the pecking response was made by a separate 'response key', all failed to show IOT. The geometric relationship between the stimulus key and the response key (upper, lower or side) does not appear to be crucial. Thus, the spatial separation of the response key and the stimulus key produced the failure of interocular transfer. These results support the idea that visuo-motor integration has the most important role in descrepancy of results of the pigeon's IOT experiments.