Modulation of the pair housing induced feeding suppression.

The present experiments explored how manipulating the period of individual housing, partner novelty, or short periods of conspecific interaction affected the feeding suppression evident when young adult male rats were moved from individual to pair housing. In the first experiment, after a period of pair housing, rats were individually housed for 0, 3, 10, or 14 days before being rehoused with either the same or a novel partner. There was an increase in the feeding suppression as the duration of individual housing grew, and at 3 days, the novel partner produced a stronger suppression than did the familiar partner. In the second experiment, four 15-min exposures to a conspecific in a novel place preference environment did not eliminate the feeding suppression at pair housing. The third experiment found that four 90-min exposures to a conspecific reduced the feeding suppression evident at rehousing. In Experiments 2 and 3, an environment previously paired with a conspecific did not produce a place aversion. Together, these experiments suggest that the feeding suppression evident when male rats are moved from individual to pair housing can be considered a graded effect open to modulation by a variety of behavioral manipulations.