Hooded rats were reared in very restricted environments with angular, curved, or white-field stimulation. The extent of transfer from this exposure was assessed in adulthood by testing subjects for (a) learning ability in form, brightness, and pattern discrimination tasks, and (b) exploration and activity differences in an open field. The angle-reared group performed better than the other two rearing groups in all three discrimination tasks. Moreover, the curved and white-field groups were equivalent. These learning differences did not appear to result from differences in (a) exploration or activity or (bl dependence on kinesthetic cues. The results demonstrated that one type of early visual stimulation produced transfer to discrimination tasks that varied in difficulty and in degree of relevancy to the rearing forms. This effect was related to the results and interpretations from previous form-rearing studies. Three interpretations were proposed for this transfer and for the advantage of angular vs. curved stimulation.

No abstract

Two levels of training (100 vs. 500 trials) and two ages of rats (young and adult) w~re used in a developmental analysis of the relationship between response strength and the effects of punishment. The apparatus was a Y maze with three discriminably different arms. After 100 or 500 reinforced trials, subjects were shocked each time they responded in one arm. The recovery sessions followed the punishment session. Results from the punishment day indicated that: (a) young rats received a greater amount of shock, and (b) additional training increased the amount of shock received by t?e young but decreased it in the adults. The recovery data showed that: (a) the suppressive effects of punishment were greater for the adults than for the young, and (b) the recovery scores were not influenced by degree of overtraining. The Age by Overtraining interaction suggested that the relationship between response strength and punishment is age dependent. The age differences found with the amount-of-shock and recovery measures provided additional support for the position that younger rats are less competent than adult rats in inhibiting responses.