International Journal of Comparative Psychology

Rats were trained on a contextual discrimination after nonreinforced

preexposure to both contexts. In Experiment 1, where contexts differed in terms of

tactile and visual stimuli, preexposure retarded subsequent discrimination by

comparison with non preexposed controls (latent inhibition). In Experiment 2, where

contexts differed only in terms of visual cue, discrimination was facilitated in

preexposed animals (perceptual learning). Food was used as reinforcer and anticipatory

activity as dependent measure. These results suggest that contextual similarity

influences the outcome of nonreinforced preexposure.