Conditional discrimination training and interocular transfer in pigeons.

Four groups of pigeons were trained either monocularly or binocularly on a series of successive line orientation discriminations. The role in interocular transfer of both changes in viewing conditions and background cues was examined. Either red or green background illumination to the patterns was used as changes in background cues; whereas alterations in viewing conditions were obtained by transferring from binocular to monocular vision, or from the left to the right eye. The results suggest that the viewing condition can operate in the same way as an external cue does for a conditional discrimination. This finding provides an explanation of the learning of conflicting discriminations with each eye by animals that also show interocular transfer.