Avoidance learning and relearning as a function of shuttlebox dimensions.

Rats in a low-ceiling shuttlebox initially show a lower level of learning than rats in a high-ceiling box. After an hour's interruption of conditioning the performance of animals in low-ceiling boxes improves and avoidance is slightly more efficient than in the unimproved performance of animals in high-ceiling boxes. Box height also interacts significantly with length of box.