Tears are a salty liquid secretion produced by the lacrimal glands located above the eye to lubricate and protect the eye. Though tears do not have an inherent smell, they can pickup odors and take on smells from things around us. Let’s take a closer look at what gives tears their scent.
Why Don’t Tears Have a Smell?
Tears are primarily composed of water, salts, antibodies and enzymes. These components do not have a noticeable odor which is why tears themselves do not have a smell. The saltiness gives tears a slightly salty taste but does not contribute a perceptible scent.
Additionally, tears drain through the nasolacrimal duct into the nose which constantly washes them away, not giving any smells time to linger or build up. So under normal circumstances, fresh tears do not have an odor that is detectable.
How Do Tears Develop a Smell?
While fresh tears are odorless, they can absorb smells from things around us. Here are some ways tears can take on scents:
- Crying while wearing perfume or scented lotion – The perfume fragrance gets picked up by the tears.
- Crying while cooking with onions or garlic – Sulphur compounds from the vegetables get into the tears.
- Crying in a smoke-filled room – The smoky smell permeates the tears.
- Crying after eating strong foods like durian or blue cheese – Volatile food compounds make their way into tears.
- Crying around pets – Tears absorb the smell of animals, their fur, and breath.
- Crying when sick with a sinus infection – Infected sinus discharge can drain into tears.
- Crying during a campfire – Smoke from the fire permeates the surrounding air and tears.
In each of these scenarios, the tears take on the ambient smells around them while flowing down the cheeks. The Brain interprets these smells as we sniffle and breathe the tears back into our nose.
Common Smells Tears Can Take On
Here are some of the most common scents tears develop based on different situations:
Onion/Garlic Smell
Chopping onions or garlic releases sulfur compounds into the air that irritate the eyes and induce crying. These sulfur molecules get picked up by the tears causing that pungent onion/garlic smell.
Smoke Smell
Whether from a campfire, cigarette smoke or forest fire smoke, the smell of smoke can permeate the air for miles. Crying with smoke around results in tears that smell like smoke.
Sickly Sweet Smell
Sinus infections and nasal congestion can change the chemical composition of nasal discharge. This infected mucus can drain into tears resulting in a sickly sweet odor.
Perfume Smell
Strong perfumes and fragrances from scented lotions get absorbed by tears. This causes tears to smell like the particular perfume or fragrance being worn.
Food Smells
Pungent foods with strong flavors like durian or blue cheese can release odor compounds. These get incorporated into tears causing them to take on food-related scents.
Pet Smells
The fur, breath and scent glands of pets release odors that tears will absorb when crying around animals. This leads to tears that smell like pets.
Measuring Tear Smells Scientifically
Researchers have analyzed the chemical composition of emotional tears versus basal tears to detect differences. Here are some scientific methods used:
Gas chromatography–mass spectrometry (GC-MS)
This technique vaporizes samples and analyzes the compounds present. Studies using GC-MS have found higher levels of certain proteins, lipids and chemical signals in emotional tears compared to regular tears.
Electronic nose technology
Electronic noses mimic the human nose using sensor arrays to detect smells. Research has utilized e-noses to demonstrate a noticeable difference in the smell of tears shed during an emotional experience compared to basal tears.
Human sniff testing
Scientists have conducted smell testing by collecting tears from donors and having panels of smell testers sniff and describe any discernible odors.
| Method | Key Findings on Tear Smells |
|---|---|
| Gas chromatography–mass spectrometry | Emotional tears contain different levels of certain proteins and chemical signals compared to basal tears, indicating a distinct composition. |
| Electronic nose technology | E-noses detect a clear difference between the smell of emotional tears versus basal tears. |
| Human sniff testing | In smell tests, human subjects could pick up distinct scents in emotional tears compared to basal tears. |
Why Smell Emotional Tears?
Researchers are interested in deciphering the smell of emotional tears because they believe it may play a role in social communication and behavioral responses.
Being able to smell when someone is crying, even without seeing them, could be meaningful. The scent could elicit empathy, comfort, or protective behavior in others nearby. Scientists are studying these potential impacts of the smell of tears.
Possible Social Communication Function
It’s hypothesized that the smell of emotional tears can send signals and relay meaning without words. People who smell the tears may intuitively recognize someone is crying or upset, prompting caring responses.
Potential Impact on Behavior
The scent of tears may unconsciously affect how others act by eliciting compassion. Further research could reveal interesting impacts on human or animal behavior in response to smelling emotional tears.
Individual Variations
The smell is thought to differ between individuals. Like other bodily secretions, the chemical makeup of tears is influenced by diet, health and genetic factors. This could lead to nuanced tear scents for different people.
Limitations of Research
While early research indicates emotional tears may have a discernible scent, more rigorous studies with larger sample sizes are needed. Some limitations to keep in mind:
- Small study sizes to date, more subjects needed
- Difficulty collecting enough emotional tears for analysis
- High variability expected between individuals
- Other factors like diet, medication can influence tear composition
- Hard to eliminate environmental confounds
Further controlled studies mapping the chemical composition of tears from more subjects would help elucidate patterns and differences in any detectable odors.
Practical Applications
Understanding the smell of emotional tears could possibly have some practical applications, such as:
Aiding Mental Health and Communication
Smelling tears could help transmit nonverbal cues between therapist and patient, or among family members. This could facilitate more empathy and connection.
Impact on Human-Animal Interactions
If pets or livestock can smell emotional tears, this could impact bonding and relationships with humans. More research is needed.
Medical Diagnostics
Noticing changes in tear smell could potentially aid diagnosis of certain illnesses. For example, an especially sweet smell could indicate sinus infection.
Criminal Justice Applications
It’s speculative, but smelling tears could hypothetically help detect lies or emotional states during interrogations. However, the accuracy would need validation.
Unanswered Questions
There is still much unknown about the smell of tears and many questions remain unresolved, including:
- How does diet, medication, health influence smell?
- Are there definitively identifiable compounds?
- Can scent intensity be quantified?
- Do different emotions result in different smells?
- How exactly does smell impact behavior?
- Do animals perceive tear smell like humans?
Ongoing research in the emerging field of chemosensory crying research will aim to address these questions and further explore the mechanisms and implications of the scent of tears.
Conclusion
In summary, tears themselves do not have an inherent smell but can take on scents from the environment. Emotional tears may have a slightly different smell compared to regular tears due to differences in chemical composition. The smell is thought to potentially serve an evolutionary purpose in communication. However, more research is needed to fully understand the range of possible tear scents between individuals, the underlying chemical compounds, and the practical applications if any. Unlocking the mysteries behind the smell of tears and its impact on human behavior remains an ongoing scientific endeavor.