Infants and Children Making Sense of Scents

This chapter summarizes research on the development of human olfactory skills to rely on different cues conveyed by odorants, such as odor quality, intensity, position in space, novelty/familiarity, and hedonic value. The sensory, neural, and psychological dimensions at the root of these early aptitudes remain poorly explored in humans, but one can safely affirm that any weak odor to which the infant has previously been nonadversely exposed will have a higher reinforcing value than any novel odor. Developmental differences in odor discrimination and appreciation are certainly causally multiple and may depend on general or olfaction-specific cognitive factors which can be traced back to prenatal or neonatal olfactory exposure effects. But some odors may also be unconditionally attractive or aversive from birth due to genetic or epigenetic factors. Increased and systematic research efforts on olfactory development during the neonate, infancy, and childhood periods are important for several basic and applied reasons. First, they can illuminate general issues on the biological, psychological, ecological, and sociological mechanisms underlying human perception. Second, findings suggest that infantile experience with specific odors can canalize lifelong perceptual abilities. These long-term effects of early chemosensory experience relate to notions, such as sensitive periods, cerebral plasticity, and memory, and also to the early programming of food liking, addictive habits, and affiliative choices.