Whether it is during a sad movie you swore you would never tear up in, or a heart-wrenching
break-up following your first love, crying may seem like a strange physical
response to your emotional turmoil. Why do we start the waterworks when we feel
really sad? Is there a biological advantage or purpose other than washing
your face or streaking your mascara? Well crying does not only happen when you are
emotional, there are actually three types of tears. Basal tears are perpetually
lubricating your eyes keeping them from drying out, while reflex tears act in
response to an irritant like onions or dust.
They begin a chain reaction releasing hormones from the brain which then
trigger a tear response from the glands in the eyelids. And these tears help to get rid
of the irritant.
But tears of sadness? Strangely this leaky face phenomenon is exclusive to
humans with a couple different theories as to why. And one is strikingly similar
to the reason we blush, which we described in a previous video here. In
many cases emotional tears are able to act as a signal to others of our
genuine sadness or distress. That is not always easy to fake. Your tears blur
your vision, essentially handicapping any aggressive or defensive actions sending
those nearby a signal of need appeasement or attachment.
From an evolutionary perspective, this increases communication with those close
to you and ultimately your chance of survival.
Some experiments have even taken photos of people crying and made copies
with the tears digitally removed. Not surprisingly, people rated the pictures
with tears to be more sad, while the ones without were often confused with puzzlement,
awe or other expressions.
But what about tears of joy? Well perhaps they are not so different, afterall tears of
happiness may still be used as social signals for how we feel, and are thought to
strengthen bonds between people. Also both emotions see activity in similar
regions of the brain, such as the hypothalamus and basal ganglia
which just happen to be connected to your tear glands.
Another theory suggests that crying is one of your body's mechanisms to
literally shed your stress. Interestingly reflex tears and emotional tears have
very different compositions. Emotional tears have much higher levels of
proteins, in particular some called adrenocorticotropic hormones
which are linked to high stress levels. And some say crying helps to release these
stress chemicals from the body, but the research here is limited and not yet
conclusive.
So go on,
have a good cry,
let the world know how you feel and potentially let out that stress.
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