Interocular transfer of lateral mirror-image discriminations by cats: evidence of species differences

Interocular transfer of mirror-image discriminations has been shown to be paradoxical in split-chiasm monkeys tested in a lighted Wisconsin General Test Apparatus (WGTA) with 3-dimensional forms, but veridical in split-chiasm cats tested in a darkened 2-choice discrimination box with transilluminated patterns. In the present study, 8 split-chiasm cats showed veridical interocular transfer of a mirror-image and a non-mirror-image discrimination in a WGTA or a 2-choice discrimination box. On the basis of the testing parameters used, it is argued that the discrepancy in the literature arises from a species difference (having a behavioral rather than a gross neurological basis), and not from differences in behavioral testing apparatus or mode of stimulus presentation.