Fetal Learning: Unimodal and Multimodal Stimulus Effects
Day, Erin Larissa
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ABSTRACT Introduction: Human newborn and animal studies provide support for the intersensory redundancy hypothesis, which posits that learning is more effective when information is presented simultaneously in two modalities than one alone. Whether the same is true in the human fetus is unknown and was examined in this study. Methods: 63 low-risk fetuses (≥36 weeks gestation) were randomly assigned to one of 6 experimental groups: each group included one of 3 stimulus conditions [unimodal (music), unimodal (maternal sway) or bimodal (music and maternal sway)], and one of 2 pieces of music (music A, 4/4 time; music B, 3/4 time) composed for the study. Laboratory pre-testing included a 2 min no-music, 2 min music (A or B), 2 min no-music observation while fetal heart rate (FHR) and body movements were recorded. Subsequently, mothers carried out the assigned intervention at home, twice a day for 5 days. On day 6, laboratory testing was repeated first with the familiar (A or B) and then the novel music. Results: The initial testing showed a difference between Music A and Music B, F (1, 61) = 8.203, p <.01, where FHR decreased to Music A and increased to Music B. The same FHR response was found when fetuses were exposed to the opposite music for the first time in the novelty testing, F (1, 44) = 4.543, p <.05, following intervention. Music A elicited a response in both the unimodal music only and sway only groups, F (29, 203) = 1.871, p < .01, and F (29, 174) = 1.818, p < .01, respectively. In music B only the multimodal group showed an effect of intervention, F = (29, 203) = 1.914, p < .005. Conclusions: Fetal response to music A and B was qualitatively different. During pretesting, FHR decreased to music A and increased to music B. When the stimulus elicited an attention response (FHR decrease) learning was observed in both the unimodal or multimodal conditions. This is seen with music A (4/4 time) music where the fetus learns the stimulus. When the stimulus did not elicit a FHR decrease (Music B, 3/4 time), there was evidence that a multimodal stimulus was more effective providing some support for the intersensory redundancy hypothesis.