The Guardian, not a journal:
Not all tears are alike. The human body produces three kinds: basal, which form an oily layer over the eyeball to keep it from drying out; reflex, which appear when an eye is bothered by cutting onions or a speck of dust and needs to flush the irritant away; and psychogenic, which are shed for emotional reasons. Notably, emotional tears have a higher protein level than basal and reflex tears, which makes them thicker and causes them to fall more slowly.
This thickness intrigues me. The longer it takes for these tears to travel down a cheek, the greater the chance that they will be noticed by another person and their message perceived. Tears are a social signal.
ringwraithfish@startrek.website 11 months ago
pubmed.ncbi.nlm.nih.gov/19568753/
They do indeed have more protein. The conclusion that it’s for them to fall slower seems to be just a hypothesis
Zagorath@aussie.zone 11 months ago
The explanation feels very much like a “just so” story to me, as much as I want to believe it.
boo_@lemmy.blahaj.zone 11 months ago
I think this is why it’s helpful to think of it, not as a ‘why’, but as a ‘how’. There are tons of things about our bodies that do not make sense, but which hasn’t killed us enough to not spread. These can still have an effect on us, and that’s what’s interesting to me.
Trying to get a reason out of evolution can be useful sometimes, when we actually want to know what lead to a trait becoming common, but for most things, especially concerning humans, the ‘how’ is so much more interesting, because we can actually get concrete answers to that.
Wirlocke@lemmy.blahaj.zone 11 months ago
I can imagine it to be the opposite.
Maybe irritant tears have less protein to not clog your vision when in a fight or threatened?
kwomp2@sh.itjust.works 11 months ago
You rock.