Abstract

The effect of rearing in isolation in later exploratory behavior was studied in A/J strain of albino mice. Twenty mice were seperated from their own litters on the 23rd day of life and reared in isolation (n = 10), or in groups of 3 (n = 10) for 60 days, before testing the exploratory behavior, Exploration was measured as contact to a discrete novel stimulus, in terms of a bout frequency and duration. Locomotor activity was measured by the number of landmark-lines traversed. Each animal was exposed to the test situation on 2 successive days, Isolation-reared mice were hyperactive, showed an increased incidence of exploratory bouts but no difference in duration of exploratory behavior, and showed a different distribution of activity while the novel object was introduced, compared with group-reared controls. Both animal groups showed no different habituation toward the test object during day 2 session. It was concluded that the isolation rearing in early life exerts facilitatory influence upon later locomotor exploration.