Restricted daily exposure to environmental enrichment increases the diversity of exploration

The temporal parameters of environmental enrichment have been examined in two ways. The first is by limiting the total duration of environmental exposure. The effects of this procedure are well documented for both physiology and behavior. The second method is by restricting the daily exposure to environmental enrichment while keeping the days of exposure constant. The physiological effects of this procedure have been documented, but the behavioral effects which have been observed are equivocal. The purpose of the present study was to address this issue. Male rats were individually housed at 44 days of age. They were then randomly assigned to either an enriched environment or an impoverished environment. The enriched animals (EC) were exposed to the enriched environment for 2 hours daily for 30 days while the impoverished animals (IC) were handled daily but not exposed to the enriched environment. Animals were then tested on an object exploration test. The results indicate that 2 hours of daily environmental exposure is sufficient to produce object exploration effects similar to those produced by 24 hours of daily environmental exposure.