Do infants smell delicious? A 2013 study in Frontiers in Psychology used brain imaging to show that the scent of 2-day-old infants activates the reward related areas of the brain (1). This activation didn’t show up in the olfactory cortex where you might expect, but in the reward areas: the same areas activated by yummy food like chocolate, or drugs. This chemosensory response occurred in all women studied (and it’s unfortunate that only women were studied). This process may have evolved so that the perception of infant body odor helps support bonding. The authors reported that “The participant women, independent of maternal status, demonstrated increased processing in the neostriate areas, thus suggesting that 2 day-old newborn infant’s body odor may convey cues that can motivate affect in parent or non-parent females to care for unrelated and unfamiliar infants alike”.
So what is the scent of babies? Regardless of age, all humans produce body odor. It’s composed of innumerable, distinct chemicals. These chemicals combine to produce a unique “fingerprint” of scent. In 1982, Scent, Training to Track, Search, and Rescue explored some of the particular components of human scent (3). One of the most familiar is scurf (scaly dry skin that has been exfoliated, such as dandruff) (4), which accumulates as dust on the furniture in our homes. Extensive research since then has documented how diseases (such as heterogeneous cancers and Parkinson’s Disease (6)) produce scents, which are detectable by some humans, and sniffer dogs, in breath and metabolic byproducts such as sweat (5).
There are myriads of additional chemicals in body odor, many even less familiar. Unfortunately we lack sufficient vocabulary to characterize these odors, or even scents in general. For example, we might say that babies smell “like baby powder”, but it’s difficult for us to speak to details beyond that. The fact that we don’t have the words is a reflection of our incomplete understanding of how body odor is perceived and how it affects behavior.
In the Particle (an Australian science-technology website), Karl Gruber described how smells produced by human bodies may reveal a wide variety of information: including age, disease, age, personality and political taste. He cited a 2012 study which compared body odor samples of groups of people in their 20s, up to 95 years of age (2). The people from 75-95 years old had a distinct, recognizable body odor. Johan Lundström characterized it in the associated press release: “Elderly people have a discernible underarm odour that younger people consider to be fairly neutral and not very unpleasant”.
In conclusion, the field of body odor is ripe for future investigation. Like other animals, it appears that human body odor may transmit signals that help people to bond with infants, distinguish kin, identify age, pick partners, and avoid sick individuals, even when we can’t find the words to describe what we smell. Detection dogs aren’t likely to lose their jobs soon, as humans strive to appreciate the elusive world of scent.
RESOURCES
- Lundström JN, Mathe A, Schaal B, Frasnelli J, Nitzsche K, Gerber J and Hummel T (2013) Maternal status regulates cortical responses to the body odor of newborns. Front. Psychol. 4:597. doi: 10.3389/fpsyg.2013.00597. Downloaded from https://www.frontiersin.org/articles/10.3389/fpsyg.2013.00597/full
- Gruber, K. What Body Odor Says About You, The Particle, April 30, 2018. Downloaded from https://particle.scitech.org.au/people/scent-of-life-you-are-an-unsuspecting-source-of-odours/
- Pearsall M and Verbruggen H (Scent, Training to Track, Search, and Rescue. Loveland, Colorado, Alpine Publications Inc.
- Definition of scurf in the Free Dictionary by Farlex, at https://medical-dictionary.thefreedictionary.com/scurf
- Canine Olfaction Science and Law (Advances in Forensic Science, Medicine, Conservation, and Environmental Remediation), Ed. Tadeusz, J. et al. (2016).
- Wife Detects Parkinson’s by Change of Husband’s Scent, https://nosework.huntersheart.com/2017/12/20/wife-detects-parkinsons-by-change-of-husbands-scent/
