Bell, Robert Wayne, 1931-||Doty, Larry A.
M.A. (Master of Arts)
Department of Psychology
Three levels of unavoidable electric shock, control (0.00 ma), low stress (0.25 ma), and high stress (0.50 ma), were administered during either days 1-5, days 6-11, or days 12-17 of the gestation period of the rat. Half of the offspring from each group were cross-fostered. All offspring were weighed and given a two minute trial in an open field apparatus at twenty-one, forty-two and fifty-six days of age. All offspring were given ten avoidance conditioning trials per day for ten days followed by three days of ten extinction trials per day from the forty-third day through the fifty-sixth day. Three shock levels were used in the conditioning trials: 0.25 ma, 0.50 ma, and 1.00 ma. The adult body weight of the offspring was found to be proportionately lower the later in the gestation cycle the stress had been administered. Particularly, the prenatal stress resulted in a reduction in the adult body weight of animals that had not been cross-fostered. Cross-fostering the control offspring reduced their weight. Cross-fostering the low stress offspring from the first two trimesters increased their body weight but no effect was found with the third phase low stress animals. Cross-fostering the high stress offspring from the first two trimesters had no effect but raised the body weight of the third trimester offspring. The activity measures showed that the stress animals from the first trimester were more active than first trimester control animals. Stress animals from the second and third trimester were less active than the respective control animals. Cross-fostering the control animals always raised their activity levels. Cross-fostering the stress animals raised their activity levels with respect to the noncross-fostered stress animals, but they were still less active than the controls. The defecation and urination measures resulted in contradictory inferences about the "emotionality" of the offspring. The conditioning data showed that the third trimester animals performed the best with the first trimester animals performing the poorest. Prenatal stress was found to lower the conditionability of the offspring. The utility of making inferences about the "emotionality" of the offspring was discussed in the light of a factor analysis which showed three factors were operative in the activity in the open field. The conditioning scores showed significant factor loadings on four factors, suggesting that the learning ability of the offspring does not constitute a unitary trait.
Davis, James Russell, "The effects of various intensities of prenatal shock administered during different trimesters of pregnancy on the emotionality and avoidance learning ability of rat offspring" (1967). Graduate Research Theses & Dissertations. 5720.
ix, 164 pages
Northern Illinois University
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