Craig:  Hi.  This is Craig and this is Mental Floss on YouTube. (crying sounds)  Today I'm going to answer Briana Stanhope's big question, Why do people cry?  Well, Briana, you're in luck because crying is what I know best.  Let's get started.

[Intro]

This is a complicated question because people cry for tons of reasons.  Babies need to cry because they're babies.  Adults sometimes cry because they're happy or sad, or they have an eyelash caught in their eye, or Charlie from Lost just died or something.  So, let's just stick to why people cry when they're emotional for the sake of this episode.

So, first, let's like talk about the actual physical act of crying.  Though it may seem like a reflex, there's a part of the brain that controls it.  The amygdala notes the emotions and sends the signal to the hypothalamus which alerts the sympathetic nervous system.  And then, here come the vapors.  That's the same nervous system connected to fight or flight, which is why other functions happen when we cry, like an increased heart rate.  

Another thing that gets alerted is the lacrimal gland, which can be found between the eyelid and the eyeball.  When something emotional happens, your brain sends a signal, then the lacrimal gland makes a tear, which causes you to blink.  Then the tear either runs down your cheek, or gets drained into something know as the lacrimal punctum, the name of my high school band. 

So, this is a human response that evolved, which means it probably has some benefits, and experts have figured out a few.  Like, emotional tears actually contain leucine enkephalin, a natural pain killer.  So lick those tears.

And that kind of explains why we cry.  It makes us feel better, which you may have personally experienced after a good cry.  Don't lick other people's tears though.  Lick your own.

Some experts also believe that crying evolved as a social cue to indicate that something is wrong.  People tend to be sympathetic towards a person who's crying, so it has a social benefit.  

(crying sound)  Love me.  Come on guys, love me.  I try really hard on these videos.

This would have particularly helped before humans developed language, because crying indicated that someone was hurt or needed help.  Experts also considered gender differences when hypothesizing about why people cry.  According to a couple studies from the past few decades, women cry more than men.  One study from the 80s, found that on average men cried 1.3 times a month (I guess I'm above average), and women cried 5.3 times.  And this accounted for every type of crying, including moist eyes.  So, yeah, it counts.  Your eyes were watering at the end of the movie Inside Out fellas, you were crying.  You were crying.  

There are probably a few reasons why men cry less than women.  Some of it might be biological.  Like testosterone may interfere making men less likely to cry.  There are also environmental factors.  Women and men cry similar amounts, on average, in countries that frown upon emotional expression.

Thanks for watching Mental Floss on YouTube, which is made with the help of all of these nice crybabies.  If you have a big question of your own, leave it below in the comments.  See you next week.  
(crying sounds) I already miss you.