Data obtained by the author and his colleagues on deficits in learning in cats reared in the lab breeding colony are reviewed. As compared with cats who lived free in a farm during the first 3-4 months of life, the lab-reared cats showed a dramatic impairment of delayed response learning to visual and auditory stimuli. They also showed some impairment of visual discrimination learning: they commited more errors than farm-reared cats when a discrimination apparatus had a partition between the stimuli, their reaction times were longer, and after lesions of the superior colliculus-pretectum complex their relearning was impaired. Thus, even moderate impoverishment of environment can considerably affect later learning ability.