ROLE OF MATERNAL DISTURBANCE AND TEMPERATURE CHANGE IN EARLY EXPERIENCE STUDIES

This study was designed to compare temperature and maternal variables as possible mediating factors in infantile treatment effects. Groups of infant rats were handled with and without temperature reduction on Days 2-7 after birth. Additional groups were handled with temperature reduction, but one group was returned to the mother cool and the other group was returned to the mother warm. Still another group of pups was untreated, but the mothers were molested in the same way as were mothers of handled animals. As adults, all animals were tested for 4 days in the open field. Following the final testing session, blood samples were obtained for an assay of adrenal corticosterone activity. The measures used in the open field did not discriminate the groups. On the plasma corticosterone measure, regardless of whether or not treatment in infancy had involved a reduction in temperature and regardless of whether they had been returned to the mother cool or warm, all handled groups were significantly lower than the like-sex control group. Furthermore, offspring of the molested mothers, although they had received no direct infantile treatment, also showed a lower corticosterone level than the like-sex control animals. This finding definitely implicates the mother in the early handling effects. © 1969.