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  • 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.

  • Got a burning question you want answered?

  • Ask it in the comments, or on Facebook and Twitter. And subscribe for more weekly science videos.

Whether it is during a sad movie you swore you would never tear up in,

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B1 emotional stress tear basal reflex response

Why Do We Cry?

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    VoiceTube posted on 2022/02/27
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