Psychosomatic Medicine 30:62-71 (1968)
© 1968 American Psychosomatic Society

Physiological and Behavioral Effects of Different Sequences of Preweaning Shock in Rats

¹ Department of Psychology, Oberlin College, Oberlin, Ohio

Wistar rats were divided into 9 groups. Six groups received different amounts and patterns of preweaning shock stress, 2 were handled in different situations, and 1 remained undisturbed prior to weaning. Adult defecation scores indicated that (1) spacing stimulation reduces subsequent emotionality, (2) little difference occurs as a result of different patterns of preweaning shock, and (3) preweaning stimulation affects later emotionality and reactivity to an adult stressor in different ways. There were no differences in organ weights or avoidance learning between groups receiving varying patterns of preweaning shock. Handled groups were heavier and had higher heart/body and kidney/body weights and lower adrenal/body weights than either shocked or undisturbed groups. Significant between-litter effects were found on open-field and body-weight measures. The adequacy of a unitary concept "emotional reactivity" for describing the effects of early stimulation on emotional behavior is questioned.