Postnatal effects of prenatal sound stimulation in the guinea pig

Pregnant guinea pigs were stimulated with a natural sound alien to their species. Postnatally the response of their young to this sound was compared with that of unstimulated controls. All young were tested with a series of the alien sounds followed by series of guinea pig calls. Heart rate changes showed that prenatally stimulated young responded less to the alien sounds than did controls, whereas both groups responded equally to guinea pig calls. Response of controls diminished during daily test sessions and over the five test days and comparison with an older control group showed that this was due to repetition of the stimulus. It is suggested that the response of prenatally stimulated animals had waned before birth.