Effect of controlled rearing on the development of stimulus-seeking behavior in rats

In three experiments, the performance of differentially reared rats was compared at 15 through 90 days of age in an experimental situation in which the amount of self-exposure to various lighted displays was being measured. The kind of visual array preferred by these animals was significantly influenced by both their ages and visual stimulation histories. Preference for light arrays involving features significantly increased in the case of light-reared and bias-reared rats beginning at 60 days of age. At the same time, a preference for diffuse light stimulation emerged in the case of their dark-reared (DR) controls. Although the significant increase in light-seeking exhibited by all groups of animals at 60 days of age was found to be unrelated to previous testing in the situation, the visual experience associated with repeated tests did "protect" DR rats from the decline in light-seeking observed after prolonged visual deprivation. Potential species differences and the nature and specificity of these changes in visual behavior are further discussed with respect to the role of early experience in visual development.