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Christopher Halliwell

Secondary Education Physics, Mississippi State University

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What is the advantage of evolving the ability to cry?

Is it simply a result of evolving the ability for complex emotions?


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  • Mar 20 2013: What evidence do you have that we evolved the ability to cry? Can you prove we didn't always have that ability? Just speaking to science, never religion.
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      Mar 20 2013: This is a great question. There seems to be an implied assumption that all abilities and features possessed by humans and other living creatures must have "evolved" and must have played some role for "survival of the fittest". This statement seems to be as unfalsifiable as the implied assumption that all creatures we see with all abilities they have have been "created".

      But what if crying is one of those numerous random mutations that have no advantages for survival whatsoever and, eventually, will disappear or just stay there because it does not lead to extinction either?
      • Mar 20 2013: Arkady, I mostly agree, from my perspective, science does not prove evolution and religion does not prove its position. However, our tears do wash unwanted things out of our eyes. By what medical specialists claim, we need our eyes to remain moist or bad stuff happens.

        My question is, could eyes do without moisture constantly? I will do a little research on the next part and that is, do our tear ducts supply the constant moisture needed for our eyes.
        That's something I never thought about before.

        Have a good evening Arkady,


        Ya made me think, thank you. :)
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        Mar 20 2013: I thought of the same thing as Jim.

        If you've ever had something in your eyes.....like a lash or a small speck of something, your eyes well up with tears right away to get the foreign object out.

        Could sadness be a foreign object in our mind's eye.......and therefore the brain creates tears to "let go" of this foreign object, that is, our sadness?

        I personally have laughed so hard that I have cried. And I have seen others do so as well.
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          Mar 21 2013: I understand the function of tears. But what's the function of emotional crying when there is nothing wrong with the eyes?
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          Mar 21 2013: Mary,
          What you are suggesting seems very consistant with scientific research, which indicates that crying and laughing may be emotionally healing.Supposedly, based on what I have explored on this topic, the same kind of healing endorphins are released in the body/mind when we cry and/or laugh.

          You ask...."But what's the function of emotional crying when there is nothing wrong with the eyes?"

          It feels like a release.....it just FEELS good when it is needed. I don't think it's a matter of "evolving the ability to cry". I think it is simply a matter of allowing a natural process to happen.
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        Mar 20 2013: Arkady, dont you think if tear glands and crying are random mutations, then how are tears present in all humans? Humans prefer to have tears, just based on the prevalence and survival of Tears. Have you ever heard of a person with no tear glands? You probably can find some on google, but they are infinitesimal. I believe It is safe to say that tears were a very primitive terrestrial adaption. Preterrestrial animals were all Marine and are used to an abundant amount of moisture around they're visionary senses (i.e. the eyes). When Continents in earth formed, marine habitats were destroyed and many organisms had to approach new 'waters', and it was what we know as continental earth. Only the fittest animals were capable of transitioning into terrestrial(LAND) organisms. Land was very dry unlike the ocean, so animals who had dryed out eyes have bad or no vision and therefore less chance of survival. Animals who developed tears to keep moisture around their eyes are probably the ones that passed their offsprings, therefore continuity and increase in alele frequency. It is hard to see how Arkady thought of this question. if we lose our tears doesnt mean we all are gonna die and our reproductive capabilities are gone. Well the thing is you never know, because it's all chance and probabilities.
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          Mar 21 2013: What you say applies to the functionality of tear glands. Christopher's question clearly pertains to emotional crying. How does that help us survive?

          Re: "dont you think if tear glands and crying are random mutations, then how are tears present in all humans?"

          Correct me if I'm wrong. It is my understanding that the theory of evolution considers that all biological advances started as random changes. Otherwise, you have to admit that life and evolutionary progress has a "purpose" which leads to creationism. Random mutations spread across species through reproduction. I'm not a biologist, though. I may be wrong.
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          Mar 21 2013: Solaiman, I love the quote from your profile:
          "My TED Story
          I was scrolling around the appstore in my newly unlocked iphone, and I was like *tap*, and then thats it.."

          This, in my view, is a very nice summary of how evolution and scientific discovery work :-).
      • Mar 21 2013: it's not that simple, there's a third option: that crying is a part of some other process that is very necessary, a kind of side effect. there might also be 4th of 5th possibilities that neither of us has thought of!
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          Mar 21 2013: Arkady what you said was completely correct. oh man. I just realized that tears dont necessarily act as defense mechanism because people also cry of joy; and what harm would joy do to someone's body(?!) my best guess emotions affect a part of our brain which we still cant comprehend and psychology. Im blabbering. Im not in a position to speculate cuz im no expert and i have no references to what im saying.
          It's fun to speculate :PPPP I actually just turned sophmore, biology is my niche

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