Psychol Rep. 2005 Oct;97(2):631-8.
Exploratory behavior as a function of environmental
novelty and complexity in male and female rats.
Pisula W, Siegel J.
Laboratory rats show a positive response to low- and nonstressful novel events. The novel event
may involve a number of aspects of the stimulus field. It is usually associated with a change in
amount of environmental complexity. Most studies concerning novelty-related behavior involve
the introduction of novel objects or the rearrangement of familiar objects. The present purpose
was to measure exploratory behavior in response to environments of increased and decreased
complexity. Both directions of environmental change are conditions of novelty. A two-way
manipulation of increasing and decreasing the complexity of the environment was used. Rats of
both sexes showed increased exploration to exposure to novelty, no matter which manipulation
was applied; however, female and male rats behaved differently to the two types of novelty.
Males responded more to novelty from the introduction of an unfamiliar object. The results
indicate novel stimulation, whether of increasing or decreasing complexity, has reward
properties. Perhaps the male-specific behavior directed toward unfamiliar objects may serve an