A study probing why people cry when chopping onions finds a mismatch between what volunteers say and what they can actually smell—suggesting many people may not accurately judge their own chemosensory sensitivity.
Chopping onions is supposed to be simple. You slice. You cook. You wipe your eyes and carry on.
But the tears are real. triggered by a chemical—syn-propanethial-S-oxide—that gets sprayed into the air and sets off the trigeminal nerve. From there, the tear ducts kick in to wash away the irritant. The problem is that even this well-known mechanism has a missing piece: whether different people really react differently. and whether their self-assessments match their actual sensitivity.
Thomas Hummel and his colleagues set out to test that gap in a “preliminary investigation” published on 25 May in Laryngoscope Investigative Otolaryngology. In the study. Hummel’s team recruited 1001 volunteers and asked them to rate their sense of smell. the general state of their nasal passages. their sensitivity to stinging and burning sensations. and their propensity for crying over onions.
They didn’t stop at questionnaires. Participants also took psychophysical tests, including identifying sticks infused with odours.
The patterns that emerged were telling—in a way that left everyone in the kitchen. so to speak. wondering who’s really reading the signs correctly. People who self-reported more tearing while cutting onions also self-reported having a better sense of smell. But the psychophysical tests didn’t back up those self-reports. Volunteers who said they were prone to crying over onions didn’t perform any better on the sniff tests than those who said onions didn’t bother them.
When Hummel’s team wrote that “No research to date has explored subjective individual variability in onion tearing and its relationship to chemosensory sensitivity. ” they were pointing to how little was known about individual differences in this everyday misery. Now the study adds another uncomfortable possibility: that people may be poor judges of their own smell-related abilities.
As the authors put it. “These findings are consistent with previous research demonstrating low correlations between subjective olfactory ability ratings and psychophysical olfactory tests.” If that sounds familiar. it’s because it echoes a common human weakness—confidence that isn’t supported by measurement. from self-assessed driving skill to interpreting complicated scientific data.
The volunteers weren’t the only ones left with questions. What looks like sensitivity—crying when onions are cut—wasn’t mirrored by performance on odor-identification tasks. That contradiction matters, because it challenges the idea that “feeling” your way to chemosensory sensitivity is reliable. If self-report can drift away from test results. then how people interpret their own reactions could vary for reasons unrelated to actual detection ability.
The irony is hard to miss: the evidence for who tears more isn’t in how intensely someone says onions affect them, but in what their senses can do when they’re measured. In other words, you may want to trust your eyes when the onion hits—but not necessarily your explanation for why.
onions syn-propanethial-S-oxide trigeminal nerve olfaction chemosensory sensitivity Laryngoscope Investigative Otolaryngology psychophysical tests
So basically my onions are lying to me? Lol
I knew I wasn’t just “dramatic” when onions made me cry. But if the sniff tests don’t match what people say, then how are they even measuring it right? Sounds like a lot of guessing.
Wait, you can “rate your sense of smell” and it’s not true? That’s wild. I’m thinking maybe people just say they tear more because they remember it more, not because they actually smell it. Also onions do more than trigeminal nerve right? Like it feels personal.
This is making me overthink my whole kitchen routine. Like if I cry more, am I just reporting it wrong? I always thought some people were just genetically more sensitive, but the article’s saying the self-report doesn’t match the tests? Idk, I feel like the tests must be flawed or they didn’t use the right kind of onions. I mean, sweet onions are different from yellow onions right?