Abstract
In all studies varying size of rearing group, cage size has been confounded with size of rearing group. Thus extinction of natural responses due to living in a larger cage could make group-housed Ss appear to be less emotional than individually housed Ss. 24 albino rats were divided into three conditions: individually housed in small cage, individually housed in large cage, two Ss housed in large cage. After 6 wk. all Ss were tested in an open field and measures recorded were center entry, corner occupancy, number of lines crossed, rearing, grooming, and freezing. Cage size was found to have a slight effect but not sufficient to explain the differences in emotionality found in studies of group vs individual housing.