Personal Olfactory Identification Information

 

Two things we will never fully understand, the human body, and olfaction, together.

Researchers explain the dissimilar smells of babies and teenagers

Mar 2024, phys.org

https://phys.org/news/2024-03-dissimilar-babies-teenagers.html

The researchers recruited the parents of 18 children aged up to 3 years old to wash the youngsters with a fragrance-free gel and to take swap samples of the armpits of their pajamas prior to sleep. They did the same with 18 teenagers between the ages of 14 and 18. All the cotton pads were then collected and analyzed in a lab setting.

The research team used mass spectrometry to identify the chemical compounds in the pads, and used gas chromatography along with a human sniffer to assess the odorousness of the smells associated with each chemical compound.

The researchers found that most of the chemicals responsible for body odor were similar between the two groups of volunteers. But there were a few that made the difference. Teenage sweat, for example, had high levels of many kinds of carboxylic acids, which the assessors described as "earthy, musty or cheesy."

They also found two steroids in the teen sweat not present in the baby sweat, one of which resulted in "musk or urine-like" emanations - the other, the assessors suggested, smelled more like "musk and sandalwood." Without such chemicals, the sweat of babies smelled much sweeter.

via a team of aroma chemists at Friedrich-Alexander-Universität Erlangen-Nürnberg with psychologists from Technical University of Dresden: Diana Owsienko et al, Body odor samples from infants and post-pubertal children differ in their volatile profiles, Communications Chemistry (2024). DOI: 10.1038/s42004-024-01131-4

https://dx.doi.org/10.1038/s42004-024-01131-4

Image credit: AI Art - Machu Picchu Face Girl - 2025

Clothes are like your second skin, so we can also call this body odor:

Textile scientists offer fresh insights on why some clothes get smellier

Jul 2024, phys.org

https://phys.org/news/2024-07-textile-scientists-fresh-insights-smellier.html

Cotton and viscose, which are cellulosic, or plant-derived fibers, absorbed - and consequently released - smaller amounts of odor-causing compounds than polyester, nylon and wool.

"Although we know that polyester is smellier after being worn next to sweaty armpits compared to cotton T-shirts, we haven't really known why."

"If you had a sweaty armpit that never actually touched the shirt you're wearing, then the fabric wouldn't get very smelly." The researchers soaked the fibers in the sweat solution for different periods of time, then examined the release of various odor-causing compounds.

Sweat is mostly made up of water but also has oily compounds that bacteria transform to form odors, and these oily compounds in watery sweat can interact differently with textiles, depending on the fiber chemistry.

"While water-loving cellulosic fibers such as cotton and viscose absorb more of the water from sweat than polyester does, polyester doesn't want to absorb the water. It's more oil-loving, and it absorbs more of the odorants, which don't dissolve in water, and more of the oily compounds.

The research also showed that although nylon and wool initially took in a lot of the odorants from the sweat, they dissipated them more quickly than polyester. After 24 hours, wool and nylon had much lower intensities of the odorants and were more similar to the cellulosic fibers.

"That tells us that while polyester still needs to be washed, for nylon and wool garments, people might be able to freshen them by just airing them out rather than laundering every time."

Bonus:

"The study's method of using simulated liquid sweat also offers an important fresh approach to exploring the issue."

via New University of Alberta and University of Otago in New Zealand: Rachel H McQueen et al, Textile sorption and release of odorous volatile organic compounds from a synthetic sweat solution, Textile Research Journal (2024). DOI: 10.1177/00405175241249462

https://dx.doi.org/10.1177/00405175241249462

Does fertility affect a woman's body odor? Study finds no evidence

Jul 2024, phys.org

https://phys.org/news/2024-07-fertility-affect-woman-body-odor.html

The researchers took samples of underarm odor from 29 women on 10 days spread over a menstrual cycle. A group of 91 men were then asked to rate the odor samples. In 16 of the women, the research team also looked at whether the chemical composition of the odor samples differed between the women's fertile and infertile days.

The results of both tests pointed in the same direction: there was no evidence from the odor ratings that men found a woman's odor more attractive on her fertile days than on her infertile days. 

Chemical analysis of the odor samples also showed no correlation between the composition of the underarm odor and the women's current fertility status.

via Leipzig University, the Max Planck Institute for Evolutionary Anthropology and the University of Göttingen: Madita Zetzsche et al, Combined perceptual and chemical analyses show no compelling evidence for ovulatory cycle shifts in women's axillary odour, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2023.2712

https://dx.doi.org/10.1098/rspb.2023.2712

Olfactory Otherness

I have a crazy idea there's a correlation between the rise of anxiety in a population and the decline in body odor due to deodorant and hygiene practices, as well as due to the increased availability of privacy, which is what I'll call the ability for each of us to have our own bedroom when growing up, or to live in an apartment alone as an adult, things that weren't available back in time because of financial constraints. That being said, the studies below do seem to suggest that smell has a stronger effect on our emotional states and our mental health status then we are aware of. 

Research shows that sniffing women's tears reduces aggressive behavior in men

Dec 2023, phys.org

https://medicalxpress.com/news/2023-12-sniffing-women-aggressive-behavior-men.html

Science strikes again!

• They use the words "emotional tears" just to clarify. (not all tears are created equal)
• The men played a two-player game where they were allowed to get revenge on the opponent.
• Revenge-seeking aggressive behavior during the game dropped more than 40% after the men sniffed women's emotional tears.

via Weizmann Institute of Science: Agron S, de March CA, Weissgross R, Mishor E, Gorodisky L, Weiss T, et al. (2023) A chemical signal in human female tears lowers aggression in males. PLoS Biology (2023). DOI: 10.1371/journal.pbio.3002442

https://dx.doi.org/10.1371/journal.pbio.3002442

Mostly unrelated image credit: AI Art - Drug Addicted DJ MK Ultra In Cybernetic Prison - 2025

Scents might help depressed individuals, new study says

Feb 2024, phys.org

https://medicalxpress.com/news/2024-02-scents-depressed-individuals.html

Scents are more effective than words at bringing back a memory of a specific event and could even be used in the clinical setting to help depressed individuals get out of the negative thought cycles and rewire thought patterns, aiding faster and smoother healing.

"It was surprising to me that nobody thought to look at memory recall in depressed individuals using odor cues before"

Professor Young presented study participants with a series of opaque glass vials containing potent familiar scents—from oranges and ground coffee to shoe polish, and even Vicks VapoRub. After asking participants to smell the vial, Young asked them to recall a specific memory, whether good or bad.

via University of Pittsburgh: Kymberly Young et al, Recall of Autobiographical Memories Following Odor vs Verbal Cues Among Adults With Major Depressive Disorder, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2023.55958

https://dx.doi.org/10.1001/jamanetworkopen.2023.55958

 

Study finds social interactions and olfactory cues prompt contagious itch in mice

Jun 2024, phys.org

https://medicalxpress.com/news/2024-06-social-interactions-olfactory-cues-prompt.html

Contagious itch only occurs in mice when they observe if a mouse that has been in their proximity is scratching.

Anosmic observer mice, whether itch-naïve or itch-experienced, displayed no contagious itch behavior.

via Tehran University of Medical Sciences: Shayan, M. et al. Social interactions and olfactory cues are required for contagious itch in mice. Scientific Reports(2024). DOI: 10.1038/s41598-024-61078-3.

https://dx.doi.org/10.1038/s41598-024-61078-3

Research shows young infants use their mother's scent to perceive faces

Jul 2024, phys.org

https://medicalxpress.com/news/2024-07-qa-young-infants-mother-scent.html

We tested 50 infants aged from 4 to 12 months, and found that the face-selective EEG response increases and complexified, indicative of improved face perception with development.

As expected, we also found that the benefit of adding the mother's body odor diminishes with age, confirming an inverse relation between the effectiveness of visual perception and its sensitivity to a concurrent odor.

Overall, this demonstrates that visual perception actively relies on odor cues in developing infants until the visual system becomes effective by itself.

What surprised me the most, not only in these studies but also in the previous studies we conducted, is the fact that the mother's odor has such a strong effect on the perception of various unfamiliar faces ... by showing reduced reactions to fearful faces, higher attention toward an unfamiliar woman, and increased interbrain synchrony between the infant and that woman.

Thus, it seems like the mother's body odor reassures the infant and promotes their interest when they encounter novel people. In other words, this primary social odor that infants learn already in the womb seems to encourage prosocial cognitions and behaviors.

via Society for Research in Child Development, Development of Olfactory Communication & Cognition  Lab in the Center for Taste, Smell and Feeding Sciences at Université de Bourgogne, University of Hamburg, Université de Lyon, Institut Universitaire de France, Université de Lorraine, Centre Hospitalier de Nancy, and Centre National de la Recherche Scientifique CNRS: Olfactory-to-visual facilitation in the infant brain declines gradually from 4 to 12 months, Child Development (2024). DOI: 10.1111/cdev.14124

https://dx.doi.org/10.1111/cdev.14124

Smell of human stress can affect dogs' emotions, leading them to make more pessimistic choices

Jul 2024, phys.org

https://phys.org/news/2024-07-human-stress-affect-dogs-emotions.html

Dogs experience emotional contagion from the smell of human stress.

The researchers recruited 18 dog-owner partnerships to take part in a series of trials with different human smells present. During the trials, dogs were trained that when a food bowl was placed in one location, it contained a treat, but when placed in another location, it was empty. Once a dog learned the difference between these bowl locations, they were faster to approach the location with a treat, which reflected 'optimism', while a slow approach indicated 'pessimism'.

These trials were repeated while each dog was exposed to either no odor or the odors of sweat and breath samples from humans in either a stressed or relaxed state. The stress smell made dogs slower to approach the ambiguous bowl.

via University of Bristol Veterinary School: Parr-Cortes, Zoe ; Muller, Carsten T ; Talas, Laszlo et al, The odour of an unfamiliar stressed or relaxed person affects dogs' responses to a cognitive bias test, Scientific Reports (2024). DOI: 10.1038/s41598-024-66147-1

https://dx.doi.org/10.1038/s41598-024-66147-1

Emotional body odors may enhance the effect of mindfulness therapy

Nov 2024, phys.org

https://medicalxpress.com/news/2024-11-emotional-body-odors-effect-mindfulness.html

48 women with symptoms of social anxiety and 30 women with depression were divided into three different groups exposed to either happiness body odor, fear body odor, or clean air, then tasked with performing mindfulness exercises over two consecutive days.

"The results were quite surprising as we observed an enhanced symptom reduction for individuals with social anxiety that received chemosignals, regardless of whether they came from fear or happiness body odors. This may indicate that it is not the emotion itself that leads to the improved effect, but perhaps rather that chemosignals convey a kind of 'human presence.'"

Two nuanced results: 1. Exposure to fear body odor resulted in lower heart rate variability indicating a less relaxed state even though this was not reflected in the self-reported anxiety ratings, and 2. No differences were seen for the group with depressive symptoms, only anxiety.

via Karolinska Institutet and National Center for Suicide Research and Prevention: Cinzia Cecchetto et al, Sniffing out a solution: How emotional body odors can improve mindfulness therapy for social anxiety, Journal of Affective Disorders (2024). DOI: 10.1016/j.jad.2024.10.088

https://dx.doi.org/10.1016/j.jad.2024.10.088

Non-Invasive Behavior Modification

Can someone say "mind-control deodorant"?

Once we learn to activate olfactory receptors through the eyes with lasers, you'll be "tuned" before you enter large gathering spaces to be more socially compatible with the other occupants.

 

Researchers identify neurons that 'learn' to smell a threat

Jan 2023, phys.org

https://medicalxpress.com/news/2023-01-neurons-threat.html

Researchers found that "inhibitory" neurons (nerve cells that act by silencing their synaptic partners) in an area of the brain responsible for interpreting social smells become highly active and change their function when males repeatedly meet and increase their territorial aggression. By disrupting the neurons associated with neuroplasticity—learning—in the accessory olfactory bulb, researchers revealed that territorial aggression decreased, linking changes to cellular function in the pheromone-sensing circuity of the brain to changes in behavioral responses to social threats.

"It abolished the ramping aggression that is typically exhibited," said Zuk. "It indicates that this early sensory inhibitory neuron population plays a critical role in regulating the behavioral response to social smells."

via University of Rochester Medical Center: Kelsey E. Zuk et al, Arc-Expressing Accessory Olfactory Bulb Interneurons Support Chemosensory Social Behavioral Plasticity, The Journal of Neuroscience (2023). DOI: 10.1523/JNEUROSCI.0847-22.2022

https://dx.doi.org/10.1523/JNEUROSCI.0847-22.2022

Totally unrelated image credit: I'm endlessly fascinated with psychoanalyzing the artificial mind, in this case, one which cannot understand what fingers are: AI Art - A Person Who Conceals Their Face with their Hands AKA Damn Fingers - 2023

https://lexica.art/prompt/001f1386-24b9-41be-86ff-927e52ef1073

Scientists show that odors from other people's sweat can help treat social anxiety

Mar 2023, phys.org

https://medicalxpress.com/news/2023-03-scientists-odors-people-social-anxiety.html

Social anxiety was reduced when patients underwent mindfulness therapy while exposed to human 'chemo-signals', or what we commonly refer to as body odor, obtained from underarm sweat from volunteers.

Combining these chemo-signals with mindfulness therapy seem to produce better results in treating social anxiety than can be achieved by mindfulness therapy alone".

via the Karolinska Institute and The European Congress of Psychiatry taking place 25-28 March 2023, in Paris. https://epa-congress.org/

*This work is part of the EU-funded Horizon2020 project POTION ("Promoting Social Interaction through Emotional Body Odors") 4. 

https://cordis.europa.eu/project/id/824153

Promoting social interaction through emotional body odours

https://cordis.europa.eu/project/id/824153

https://doi.org/10.3030/824153

The way chemistry influences human communication is one of the most intriguing and debated topics. More specifically, the nature of chemosignals and their sphere of influence on social interaction is a very important key to understanding human behaviour. POTION proposes a novel technological paradigm to delve deeper into understanding meaningful social interaction, combining new knowledge about the chemical composition of human social chemosignals together with a novel olfactory-based technology designed to drive social behaviour. A first challenging analysis on human chemosignals to delineate the chemical underpinnings of the emotions of happiness and fear will be carried out since they are the representative emotions that drive approach and avoidance behaviour, i.e. the fundamental building blocks of social interaction between individuals of the same species. Results of this analysis will be used to artificially synthetize the chemosignals of these two emotions, which will provide the basis of an innovative computer-controlled odour delivery system able to drive the approach-avoidance social strategy. This breakthrough device will be controlled in a closed loop by the social-emotional state of the subjects evaluated through a novel computational neural model. The POTION system will be applied and tested in both social and clinical scenarios. In the social scenarios, we venture to reveal how olfaction clues work in managing the feelings of trust, presence and inclusion, in both virtual, real, and social media contexts. In the clinical scenario, POTION will propose a new human chemosignal-based diagnosis and treatment for social anxiety, phobias and depression, which are known to all share impaired social functioning. POTION will provide further insight to the fundamental underpinnings of human behaviour with the goal to help establish healthy social relationships through trust, leading to an overall improvement in wellbeing.

Mind Control

It should come as no surprise that we look to others to help us make decisions, whether they're life-changing or everyday decisions. In a new study, we see that when mice choose what to eat, they utilize "taster mice" in their group that are the first to eat from a new food source.

I'm not sure what makes one a taster-mouse in the first place, but they do exist. In order for mice to decide at the colony level whether they should be eating from a certain food source, they don't ask their friends, and they don't check their newsfeed. Instead they use the smell of taster-mice whiskers.

In reality, mice don't do anything. Their brains are programmed by the smell of the taster-mice to steer them towards some food sources and away from others. Their repeated olfactory interactions with the taster mice and the social network they subsequently inform will rewire the neural network in their prefrontal cortex – the place where decisions are made. This alteration links the olfactory cue from the taster-mice to the reward center in the brain, which then motivates the mice to find that smell again.

We can think of all preference as following a similar pattern of social interaction and propagation. Taster-mice function as hubs of their social network. The difference is that humans are a bit more sophisticated. Instead of just transmitting the smell of safe, available food, the hubs of human networks spread styles, preferences, ideas, and information in general.

The interesting corollary is that in mice, the olfactory cues are literally re-wiring the pleasure-seeking centers of their brains, whereas in humans, all kinds of cues can redirect our behaviors. Olfaction is already known to be so tightly integrated with our decision-making and reward centers, but when the actual process by which this takes place is extrapolated to other senses, it suggests that we are way less in control of our own thoughts, desires and behaviors than we may think.

Notes

When social interaction helps you choose your food

June 2019, phys.org

Post Script

By the way, casually mentioned in the article that presented this study, was the practice of "erasing memories" in the mice in the study. It's a technique used in optogenetics where a single neuron is zapped. I'm pretty sure it was only a few years ago that we first heard of this technique, and now it's just thrown in there like de rigueur. Eternal Sunshine here we come!

Post Post Script

On Mimetic Desire:

"All desire is a desire to be [someone else]"

-Rene Girard, Quand ces choses commenceront ... Entretiens avec Michel Treguer. Paris: arléa. ISBN 2-86959-300-7. p28. 1994.