Response to novelty in rats tested in isolation and in pairs: focus on exploration and play

The main goal of the study was to compare investigatory responses towards novelty in 20 Wistar rats divided into two experimental groups (solitary exploration vs. exploration in pairs). Additionally, relationship between novelty and social play/interaction was analyzed in the dyad group. Procedure involved placing animals in an experimental chamber during fifteen, six minute trials on successive days of the study. On the eleventh session a new object was introduced. The results are summarized within several behavioral categories. Investigatory responses of rats in dyad to novel object in familiar environment were not quantitatively different, than those of isolated animals. The animals from both groups responded to the novel object by focusing their exploratory activity on the source of new stimulation. Amount of social play and social exploration was influenced by the experimental manipulation with important sex differences present.