Alone in the dark? Modeling the conditions for visual experience in human fetuses.

It is commonly assumed that, whereas auditory and olfactory learning take place already during fetal development, visual experience and learning are not possible before birth. This paper explores the conditions for visual experience in the last two months of human gestation, when the fetal visual system is mature enough to permit directed vision if a sufficient amount of light is available. Light transmission from the external environment to the uterine cavity is modeled, based on the measured transmission coefficients of biological tissues. Results indicate that illumination in the uterine cavity is highly variable, depending on factors such as external illumination and the mother's abdominal thickness. At least some fetuses can be predicted to develop in conditions allowing for ample visual experience before birth. This finding could have intriguing implications for the ontogeny of early visuo-motor abilities in newborns and infants.