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Wed 25 Oct, 2006 09:08 pm
What is the biological significance of weeping? To secrete water (and the various compounds dissolved in it in the tear) to lubricate eyes has a meaningful function, but to do it merely in response to strong emotion is just waste. Is it at all known why emotional stress causes humans to release tears in a much higher volume than normal lubricating tears?
Not everything needs to have a biological significance. That is not how biology works. That we look for "significance" in everything says more about the human mind than about any other part of the universe.
However, there is probably an advantage to species that depend on social skills and empathy (humans for example) to show visual signs of emotion.
According to wikipedia, the composition of tears from weeping differ from the composition of tears for lubrication, which is pretty interesting, but I would still like to know specifics (ie, involving chemical signaling?) explaining why emotion produces the tearing mechanism from the glands with higher volume and why exactly the composition differs from normal tears.
If you let loose a fleet of ships into the ocean, it is most efficient for the crew of each ship to mind itself. But every now and then a ship may need to recruit some help from a neighboring ship. Even though it reduces the efficiency of the helping ship a little bit, it increases the efficiency of the fleet as a whole to have a means for a distress signal. Humans are not only programmed to send out such a distress signal when we lose hope, we are also programmed to respond to their distress signal in a helping way. Who can ignore a crying female?
My training is in Physics, not in biology. So perhaps someone else can step in with a better answer. The only thing I can answer with confidence is my first point that looking for "significance" in a matter of science is folly. I am even uncomfortable with your unqualified use of the word "why?" since this question is often answered with a human interpretation of something that often is not scientifically valid.
I also hope we can agree that evolution is the only scientific way to answer this question (since evolution is the foundation of modern biology). Evolution is the answer that mainstream biologists give to this sort of questions and the discussion is in the details. If we can't agree on this, there can be no scientific discussion. So then rather than talking about significance, we should be talking about advantage.
I did a quick google search and found that speculations that crying was a good way to communicate distress is not a ridiculous idea. The few papers I read over (including the wikipedia article you reference) point out the chemical difference.
There was another article (I am too lazy to dig up the link again) that suggested that sobbing (a good way to communicate distress), but that sobbing involves quick inhaling and exhaling which can cause dryness. Extra moisture (including tears) is not a bad thing.
The evolutionary development of the social parts of our nature is very interesting to me. Unfortunately I am just a fairly well-informed amature in these things.
Are there any biology folks here who can answer better?
Quote:Emotional tears contain much more (maybe 25% more) than basal or irritant tears of a certain important ingredient: proteins(8)... The proteins found in emotional tears are hormones that build up to very high levels when the body withstands emotional stress(9).
If the chemicals associated with stress did not discharge at all, they would build up to toxic levels that could weaken the body's immune system and other biological processes. But here, as in other areas, the body has its own mechanisms of coping. We secrete stress chemicals when we sweat and when we cry. Clearly, then, it is physically very healthy to cry, regardless of whether or not it feels awkward or embarrassing socially. The reason people will frequently report feeling better after a well-placed cry is doubtless connected to the discharge of stress-related proteins(10); some of the proteins excreted in tears are even associated with the experience of physical pain, rendering weeping a physiologically pain-reducing process(8).
Excellent link and very interesting. I knew the difference in composition would tie into the explaination somehow. This is exactly the sort of physiological significance of crying I was curious about. Thank you, spidergal.
Didn't need to read your link spidergal...I know the cathartic release of a good cry...and good howler of one.
I've out of the blue just said to myself.."I'm gonna have a good cry" and do.
It relaxes the entire body, and releases mental emotional stress.
I'm too lazy right now to search this but within the last couple of weeks this question also came up on another a2k thread, and someone's scientific answer mentioned that male tears did not have the same hormonal components. Not only do I not have a link for the science answer, I don't have a link for that other thread. Schniff...
I remember seeing a bit of a movie once about a pervert who collected the tears of ladies in phials.
I can't remember what he did with them. I turned it off.
Does everything have to have a purpose? What was the "point" of the shell of the Didymoceras ?
If evolution is by random changes (I know this is very un-technical, but bear with me) is it not possible that we have some physiological trait that serves no point, but it neither hinders nor helps us, therefore we have not lost it? Or it is a hindrance and a mistake but we still have it because we are not some perfected end-point of evoultion?
Or do I miss the boat completely?
great topic
Such a great topic. this is so much fun to read.
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