Monday, November 8, 2010

Apple #492: Earlobes

My previous two entries were pretty intense, so I thought it would be good to shift back to something more relaxed.

You don't normally think too much about your earlobes, but for no earthly reason I can determine, last night, I dreamt about mine.  They grew to an enormous size, taking up the whole of my mental screen if you will, and they also took on an odd rounded hexagonal shape.  If you happen to be a dream specialist and you know that this dream means something incredibly embarrassing about me, I guess I'd rather not know.

But it did get me thinking about earlobes.  Weird things, when you think about them.  What the heck are they for, for one thing?

Nice earlobes!
(Photo from Simply Ageless)

  • Scientists say that, as far as they can tell, earlobes serve no biological purpose.  They do have a hefty blood supply for their size, but that doesn't seem to provide any particular benefits to the head or anyplace else as far as scientists can tell.  Earlobes are probably some evolutionary leftover that, in some previous form on some previous animal, did serve a purpose.  But the way they are now, on our bodies, they're pretty much decorative.
  • Which makes them a nice place to put things like earrings and tattoos and so on.
  • A lot of people say, by the way, that earrings used to be a mark of slavery and therefore you shouldn't pierce your ears.  They quote various passages in the Bible to support this.  But there are lots of other passages in the Bible that describe people wearing rings in their ears, and in those passages the earrings are described as decorative, and sometimes even celebratory. So if you want to show off those shapely lobes of yours, go for it.
  • Speaking of shapes of earlobes, you probably know that some of us have earlobes that are "attached" and some of us have earlobes that are detached or free-hanging.

The A earlobe is detached and the B earlobe is attached.
(Photos from Windows to the Universe)

  • You probably also remember from your science classes that the attached vs. detached earlobe is a genetic trait. The detached earlobe (in the photo above, A) is the dominant trait, while attached (B) is recessive.
  • This means that if you have attached earlobes, you inherited the gene from both of your parents.  Even if neither one of your parents have attached earlobes, if your ears are detached, they both must carry the recessive gene for attached earlobes. On them, since they have detached earlobes, that dominant trait outweighed the recessive, so that the attached earlobe remained not expressed, or not visible.
  • Here's another fact about the shape of earlobes that I just learned: creased earlobes may indicate that their owner has heart disease.
This guy has a creased earlobe.  Here, the crease runs almost vertically down the lobe.
(Photo from Craig's Scrapbook)

  • Scientists did a bunch of studies where they looked at people who had heart disease in some form and -- I don't know why -- they also looked at their earlobes.  They didn't do just one study, but a lot of them, and generally speaking in most of the studies, about 70% to 80% of the people who had heart disease also had the creased earlobes.
  • If you have creased earlobes, this doesn't mean you are necessarily going to get heart disease.  It also doesn't mean that if you just figure out how to uncrease your earlobes, any heart disease you may have will go away.
  • In fact, it is possible that people simply develop earlobe creases as they get older, regardless of any health issues.  It is also possible that people may develop an earlobe crease from sleeping more often on one side of the head than the other.
  • But even though there may be no direct relationship between the presence of the crease and heart disease, the critical mass of the data suggests that if you do have the crease, it might be a good idea to keep an eye on your cardiovascular health. Get your blood pressure and cholesterol levels checked out, give your body a little extra help in the cardiovascular aspect, and maybe you'll be among the 20% to 30% with creased earlobes without heart disease.
  • It is definitely known that your earlobes keep growing as you age.  They grow, on average, about 0.22 millimeters a year -- a very tiny amount, but it's there.  This is true for both men and women.  You may have noticed that earrings that used to look good on your ears when you were younger fit you differently now.  
  • It could only be gravity stretching out the collagen in your earlobes. However, some scientists have found evidence that suggests that our earlobes grow in seven-year cycles, where the rate of growth increases a bit each year until year 7, and then the growth rate drops off again and rebuilds through another 7 years.
  • If that's the case, then maybe there's more going on to make your earlobes get bigger than plain old gravity.  Your hair also grows in 7-year cycles, so it's not as if your body made up that rule for earlobes alone.  
  • Still, most scientists lay the blame for earlobe growth at the door of gravity. 
  • A lot of people online say that your earlobes line up with your nipples.  Of course I had to try to verify this.
  • I looked at a lot of pictures of shirtless people looking ahead to the camera, and based on what I've seen, I'm going to have to say that claim is not exactly true.  It looks to me that you can say the outside edge of the ear is aligned with the nipple, but not necessarily the lobe.  This is purely based on limited observation, so perhaps more study is needed.
It's tough to find a not-indecent photo of someone with his shirt off, and with his head facing the camera so you can see whether his earlobes line up or not. In this photo of Mark Wahlberg, all of these things are true. Now, see what I mean about the earlobes not quite lining up with the nipple?  The outside of the ear seems to be a better indicator. (Marky Mark's famous third nipple is also visible here.)
(Photo from Electric 94.9)

MadSci Network, Why do we have earlobes, what are they for? August 31, 1999
My Jewish Learning, Body Piercing in Jewish Law
Windows to the Universe, Are your earlobes free hanging or attached to your head?
The Straight Dope, Are earlobe creases a sign of heart disease? September 2, 2009
Dr. W. Gifford Jones, Another Look At The Earlobe Crease, Canada Free Press, December 12, 1992
University of Alabama Birmingham Dear Doctor Column, Ear Lobe Creases Don't Mean You Have Heart Disease, October 2, 2003
Reader's Digest, Why do our earlobes seem to grow longer as we grow older?
The Register, Do our ears grow longer with age? May 26, 2006
C. Niemitz et al., Human ears grow throughout the entire lifetime... (Abstract) Institute for Human Biology and Physical Anthropology, December 2007

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