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Re: [evol-psych] News: Evolution helped turn hairless skin into a canvas for self-expression

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  • Stan Franklin
    Edger, Yes, that s an issue that needs to be addressed. The only aquatic monkey I know of is the proboscis monkey that wades bipedally through the mangrove
    Message 1 of 16 , Feb 20, 2013
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      Edger,

      Yes, that's an issue that needs to be addressed. The only aquatic monkey I know of is the proboscis monkey that wades bipedally through the mangrove swamps. I haven't been able to find any information about how long this species, or its ancestors, has been aquatic, but it's been long enough for them to evolve webbed fingers and toes. Maybe losing hair takes longer, though I don't see why it would. Also the proboscis monkey is an Asian species and a denizen of dense forests. Why any of this would make a difference, I don't know. The most likely explanation is that the proboscis monkey only travels through water, wading or swimming. It doesn't eat there, which I, and Wrangham, presume early hominids did. That would keep the hominids in the water longer than the monkeys, and make having hair more of a burden. I'm not sure I buy this explanation. For the moment I'll just have to file this issue away as a problem for the shore-dwelling hypothesis as an explanation of our hairlessness. Thanks for pointing it out.

      Stan


      On Wed, Feb 20, 2013 at 6:21 AM, Edgar Owen <edgarowen@...> wrote:
      Stan,

      There are monkeys which are regularly aquatic but which show NO loss of hair... Just wading around in the water even regularly is not going to do it...

      Edgar



      On Feb 20, 2013, at 1:20 AM, Stan Franklin wrote:

      > Edgar,
      >
      > I'd prefer to attribute our hairlessness to what used to be called the
      > aquatic ape hypothesis, but not seemed to be that our hominid ancestors
      > were shore dwellers (oceans, lakes, rivers). Tropical animals that are
      > hairless are often water lovers (hippos, elephants, rhinos, pigs). Even the
      > mainstream anthropologists are beginning to come around to this
      > shoredweller theory. For example, please see Wrangham, R., Cheney, D.,
      > Seyfarth, R., & Sarmiento, E. (2009). Shallow-Water Habitats as Sources of
      > Fallback Foods for Hominins. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY,
      > 140, 630–642.
      >
      > Stan
      >
      >
      > On Tue, Feb 19, 2013 at 7:01 PM, Edgar Owen <edgarowen@...> wrote:
      >
      >> **
      >>
      >>
      >> Stan,
      >>
      >> Yes, I agree. Obviously that theory is nonsense. Much more likely the
      >> result of sexual selection as mate selection became more and more based on
      >> looks with the increasing conscious conceptualization of the world in
      >> humans as awareness increased.
      >>
      >> Edgar
      >>
      >>
      >> On Feb 19, 2013, at 12:25 PM, Stan Franklin wrote:
      >>
      >>
      >>
      >> Help!
      >>
      >> If "Hairless skin first evolved in humans as a way to keep cool..." why
      >> didn't it evolve in any of the several other primates living during the
      >> same times in the same environment?
      >>
      >> Stan
      >>
      >>
      >> On Sun, Feb 17, 2013 at 6:44 PM, Robert Karl Stonjek <
      >> stonjek@...> wrote:
      >>
      >>> **
      >>>
      >>>
      >>> **
      >>> <http://phys.org/>
      >>> Evolution helped turn hairless skin into a canvas for self-expressionFebruary
      >>> 17th, 2013 in Biology / Evolution
      >>>
      >>> *(Phys.org)—Hairless skin first evolved in humans as a way to keep
      >>> cool—and then turned into a canvas to help them look cool, according to a
      >>> Penn State anthropologist.*
      >>>
      >>> About 1.5 to 2 million years ago, early humans, who were regularly on the
      >>> move as hunters and scavengers, evolved into nearly hairless creatures to
      >>> more efficiently sweat away excess body heat, said Nina Jablonski,
      >>> Distinguished Professor of Anthropology. Later, humans began to decorate
      >>> skin to increase attractiveness to the opposite sex and to express, among
      >>> other things, group identity.
      >>>
      >>> "We can make a visual impact and present a completely different
      >>> impression than we can with regular, undecorated skin," said Jablonski, who
      >>> reports on her research today (Feb. 16) at the annual meeting of the
      >>> American Association for the Advancement of Science in Boston.
      >>>
      >>> Over the millennia, people turned their skin into canvases of
      >>> self-expression in different ways, including permanent methods, such as
      >>> tattooing and branding, as well as temporary ones, including cosmetics and
      >>> body painting, according to the researcher.
      >>>
      >>> Jablonski said both males and females use forms of skin decoration to
      >>> become more attractive to the opposite sex. Women, for example, may use
      >>> makeup to increase the size of their eyes, a cue that is considered
      >>> attractive in most cultures. Males in some cultures also use skin
      >>> decoration as a way to bring out facial features to appeal to women, or to
      >>> look more menacing and warrior-like.
      >>>
      >>> "We can paint a great design on our bodies and use those designs to send
      >>> all sorts of messages or express group memberships," said Jablonski.
      >>>
      >>> While parents may still fret that their children are choosing tattoo
      >>> designs frivolously, Jablonski said people have traditionally put
      >>> considerable time and thought into the tattoos.
      >>>
      >>> "Usually it is something with deep meaning," Jablonski said. "When I talk
      >>> to people about their tattoos they, tell me they've spent months or years
      >>> choosing a design that is incredibly meaningful and salient to them."
      >>>
      >>> Prior to the evolution of mostly naked skin, humans were furry creatures,
      >>> not unlike chimpanzees are now, Jablonski said. Skin decoration would not
      >>> be possible if humans were still covered with fur.
      >>>
      >>> Studying skin is difficult because it can be preserved only for a few
      >>> thousand years, unlike bones and fossils, which last millions of years.
      >>>
      >>> Jablonski said that she and other researchers based their estimate on
      >>> when humans evolved hairless skin on the study of the fossil record and an
      >>> examination of the molecular history of genes that code proteins that help
      >>> produce skin pigmentation.
      >>>
      >>> "We find a lot of evidence of when humans began to lose hair based on
      >>> molecular genetics," said Jablonski.
      >>>
      >>> Humans are the only primates that are essentially hairless, although
      >>> aquatic mammals, like whales and dolphins, have no hair. Prior to the idea
      >>> that humans evolved hairlessness as a mechanism to cope with body heat,
      >>> some researchers believed that hairlessness resulted from evolution from a
      >>> common aquatic ancestor, Jablonski said. However, the theory, often
      >>> referred to as the aquatic ape theory, does not match the genetic, fossil
      >>> and environmental evidence, she said.
      >>>
      >>> While it is difficult to exactly say when humans began to decorate their
      >>> skin, Jablonski said that some of the earliest preserved skin shows signs
      >>> of tattooing.
      >>>
      >>> Provided by Pennsylvania State University
      >>>
      >>> **
      >>>
      >>> "Evolution helped turn hairless skin into a canvas for self-expression."
      >>> February 17th, 2013.
      >>> http://phys.org/news/2013-02-evolution-hairless-skin-canvas-self-expression.html
      >>>
      >>> Posted by
      >>> Robert Karl Stonjek
      >>>
      >>>
      >>
      >>
      >> --
      >> Stan Franklin   Professor   Computer Science
      >> W. Harry  Feinstone  Interdisciplinary  Research   Professor
      >> Institute for Intelligent Systems
      >> FedEx Institute of Technology
      >> The University of Memphis
      >> Memphis, TN 38152 USA
      >> 901-678-1341
      >> <http://ccrg.cs.memphis.edu/~franklin/>
      >> lab <http://ccrg.cs.memphis.edu/>
      >>
      >>
      >>
      >>
      >>
      >
      >
      >
      > --
      > Stan Franklin   Professor   Computer Science
      > W. Harry  Feinstone  Interdisciplinary  Research   Professor
      > Institute for Intelligent Systems
      > FedEx Institute of Technology
      > The University of Memphis
      > Memphis, TN 38152 USA
      > 901-678-1341
      > <http://ccrg.cs.memphis.edu/~franklin/>
      > lab <http://ccrg.cs.memphis.edu/>



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      --
      Stan Franklin   Professor   Computer Science
      W. Harry  Feinstone  Interdisciplinary  Research   Professor
      Institute for Intelligent Systems        
      FedEx Institute of Technology              
      The University of Memphis
      Memphis, TN 38152 USA  
      901-678-1341
      <http://ccrg.cs.memphis.edu/~franklin/>  
      lab <http://ccrg.cs.memphis.edu/>

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