Partition between stimuli slows down greatly discrimination learning in binocularly deprived cats

Pattern discrimination learning was compared in cats reared in a normal environment during the first months of life (N cats), control cats reared in the laboratory with opened eyes (C cats), and cats deprived binocularly of patterned vision from birth (BD cats). A two-choice apparatus was used for training. In Expt. I the cats had been trained without a partition between stimuli and retrained with the partition. In Expt. II the partition was used from the beginning of training. The partition slowed down the learning in all groups. However, the BD cats were much more affected than N cats, and C cats seemed to be more affected than N cats and less than BD cats. In BD and C cats the number of errors of entering an incorrect alley without pushing the gate was increased. In contrast, when the partition was absent and discrimination very simple (stimulus vs no stimulus), the BD cats seemed to master the task even more quickly than N and C cats. The results suggest that the deficit produced by the partition consisted largely in a difficulty in rapid choosing a correct directional response at distance. In BD cats the mechanism of the deficit was complex.