International Journal of Comparative Psychology

The use of novel objects as environmental enrichment devices is a key aspect of many environmental enrichment programs, regardless of whether the animals being enriched are housed in aquaria, zoos, or laboratories. The effectiveness of novel objects as enrichment devices depends on a number of factors, many of which are based on findings from comparative psychology. For example, the literature on habituation predicts that an object that is always in an animal’s environment will be less interesting than a similar object that is available only on an intermittent basis. To test the hypothesis that type of exposure to objects affects the objects’ enriching qualities, we exposed sixteen animals from ten different species to novel objects in two different conditions. In the first condition, animals were exposed to a novel object for a total of 120 min, 60 min at a time on two separate occasions. Approximately three weeks later, the animals were once again given a total of 120 min to interact with the object that they had experienced in the first condition, but the amount of time the object was available per session was much more variable. The results demonstrate that variable presentations are more likely to maintain the enriching qualities of objects, consistent with the literature on habituation.