A Rat Performs a Memory Exercise (IMAGE) Indiana University Caption To test the rats' memory, IU researchers placed the animals inside an "arena" with different odors. The rats were rewarded when they identified the second-to-last item or fourth-to-last odor from a list of unpredictable length. Credit Indiana University Usage Restrictions Credit Indiana University License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.