Olfactory Memory - Behavioural Effects - Olfactory Cues - Human Studies

Human Studies

Research studies provide evidence that the fetus becomes familiar with chemical cues in the intrauterine environment. Intrauterine olfactory learning may be demonstrated by behavioral evidence that newborn infants respond positively to the smell of their own amniotic fluid. Infants are responsive to the olfactory cues associated with maternal breast odors. They are able to recognize and react favorably to scents emitted from their owns mother’s breasts, despite the fact that they also may be attracted to breast odors from unfamiliar nursing females in a different context. The unique scent of the mother (to the infant) is referred to as her olfactory signature. While breasts are a source of the unique olfactory cue of the mother, infants are also able to recognize and respond with familiarity and preference to their mother’s underarm scent.

Olfactory cues are widespread within parental care to assist in the dynamic of the mother-infant relationship, and later development of the offspring. In support of fetal olfactory learning, newborn infants display behavioral attraction to the odor of amniotic fluid. For example, babies would more often suck from a breast treated with an amount of their own amniotic fluid, rather than the alternative untreated breast. Newborns are initially attracted to their own amniotic fluid because that odor is familiar. Although exposure to amniotic fluid is eliminated after birth, breast fed babies have continued contact with cues from the mother’s nipple and areola area. This causes breast odors to become more familiar and attractive, while amniotic fluid loses its positive value. Maternal breast odors are individually distinctive, and provide a basis for recognition of the mother by her offspring.