Friday, December 5, 2008

why the tears?

Does anyone happen to know the *biological* or practical purpose of human tears?  Another blogger, The Dan (http://danthoms.blogspot.com/), has done a little research on eye-balls and tearing, and he reports that he cannot find any reason for emotional tears.

Now, we know that when something is in your eye, ... then tears can flush it out. But why do tears come when one is emotional (sad or happy)?  Like when one is watching a movie and is "moved," what purpose do tears serve?  When we are happy to see someone, why do our eyes get moist?

Anyone know?

Any theories out there?

4 comments:

Elaine said...

I did a little digging and found some interesting info. Emotional tears (aka psychic tears) are probably the result of increased activity of the hypothalamus when we experience extreme emotions. Emotional tears actually have a different chemical composition than regular (basal) tears in that they contain higher levels of certain hormones like prolactin, adrenocorticotropic hormone, and leucine enkephalin. One theory is that we cry in order to get rid of excess amounts of these hormones which could explain why we often feel better after crying. Ok, hope that wasn't too much information. I tend to get overly excited about these types of questions...

Michael Joseph Sharp said...

Never too much information. Thanks Elaine!

Do other mammals have similar types of tears? Or, are humans the only ones?

inverted banana dancer said...

Interesting question. Another thought is laughter. What does that mean? It is easy to see the biological basis for tears, but what purpose does laughter do? Where does it come from? Humor, a most intersting topic. Do you think it is exclusivly human? Cultutral? Whoa! Blows the mind to consider. What about laughing so hard you cry? Cha-ching!

Michael Joseph Sharp said...

Good points, IBD.

What intrigues me the most is how so radically different the human mammal is from her/his cousin. We seem to be an altogether different species, ... from a different world, ... with a different source.