Subcultural engagement for the 21st Century...
Barbelith is a new kind of community (find out more)...
You can login or register.

Underground > Conversation >

Symmetry

10:55 / 27.03.03

Kit-Kat Club going off-topic in the Strange Associations thread has got me thinking:

KKC asks why it is so difficult to distinguish between left and right. That surprised me because I've always been amazed at how easy it is. I'm not boasting about my left-right differentiation skills here (although they are legendary), it's just that since we're broadly symmetrical, there's nothing obvious to hang the 'left' and 'right' tags on. My left hand, frinstance, looks frighteningly like my right one. Sure, the thumbs point in opposite directions, but one points to the left and the other to the right, so that's no help.

Now I happen to be right-handed, so there is that difference, and so knowledge of this means that I can identify my right hand by seeing which one naturally moves to pick up a pencil. I think perhaps this is what I do when I make that lightening identification, for which I am famous. But I have a couple of questions:

(1) Do ambidexters have particular trouble distinguishing right from left?

(2) Why do we look like this - with one of everything down the middle and two of everything down the sides? I'm aware that it's not quite like that underneath the meat, but to me that just makes the surface symmetry more puzzling.

11:01 / 27.03.03

from the split of the first cell I suspect, egg in the womb. Did you know proteins have handed-ness?

11:35 / 27.03.03

how can you tell whether a protein has handedness or not?!

11:47 / 27.03.03

I can think of a few points:

If you are ambidextrous (as I am) you do not have a dominant side, you do not automatically preference one side over the other. It doesn't matter which hand or foot you use. Both sides are equal: no internal marker.

Generally most people I know who are dyslexic have a big problem with right and left, but actually they have a problem with 'labels' in general, not those concepts. It takes a much longer time to recall the meanings of those words and translate them.

I am assymetric (deformed hand) and have been all my life but still my sense of right and left is rather poor: because of this I would suggest that your sense of direction is entirely internal, based on a sense of a dominant side (ie an assymetry in your head) and not on a memory related to anything external or physical.

11:56 / 27.03.03

When the earth was still flat
And clouds made of fire
And mountains stretched up to the sky
Sometimes higher
Folks roamed the earth like big rolling kegs
They had two sets of arms
They had two sets of legs
They had two faces peering
Out of one giant head
So they could watch all around them
As they talked; while they read
And they never knew nothing of love
It was before the origin of love
The origin of love

And there were three sexes then,
One that looked like two men
Glued up back to back
Called the children of the sun
And similiar in shape and girth
Were the children of the earth
They looked like two girls rolled up in one
And the children of the moon
Were like a fork shoved on a spoon
They were part sun, part earth, part daughter, part son
The origin of love

Now the gods grew quite scared
Of our strength and defiance
And Thor said "I'm gonna kill them all with my hammer
Like I killed the giants"
And Zeus said "No
You better let me use my lightning like scissors
Like I cut the legs off the whales
And dinosaurs into lizards"
Then he grabbed up some bolts
And he let out a laugh
Said "I'll split them right down the middle
Gonna cut them right up in half"
And the storm clouds gathered above
Into great balls of fire.

And then fire shot down from the sky in bolts
Like shining blades of a knife
And it ripped right through the flesh
Of the children of the sun and the moon
And the earth
And some Indian god sewed the wound up
Into a hole
Pulled it 'round to our bellies
To remind us the price we pay
And Osiris and the gods of the nile
Gathered up a big storm
To blow a hurricane
To scatter us away
A Flood of wind and rain
And a sea of tidal waves
To wash us all away
And if we don't behave
They'll cut us down again
We'll be walking around on one foot
And looking through one eye...

12:02 / 27.03.03

how can you tell whether a protein has handedness or not?!

Molecules have a 3D shape, therefore can exist as mirror images of each other. Counter-intuitively, these mirror images can have startling different properties.

Have a look here for the Johnny Ball-lite Adam Hart-Davies explanation.

As for symmetry down the middle, surely you are only superficially symmetrical in that you have two of everything - the individual bits do vary slightly in size/shape.

My best guess would be it is simply a result of a long distant evolutionary advantage given to our 'symmetrical' ancestor - balance would seem to be the logical advantage of being the same shape - it aligns your centre of gravity which surely means it is easier to move around and therefore avoid being eaten...

Once we started on the symmetrical route, we were kinda stuck with it - even flat fish show signs of their symmetrical heritage, with one eye having moved round the head to lie next to its partner.

12:10 / 27.03.03

This is interesting, even if it doesn't answer your question. Quote:

"Another chapter I found particularly interesting, "Eyes Right!," involved an elderly woman who had suffered a stroke affecting her right cerebral hemisphere. As a result, she lost visual perception in her left visual field. What's more interesting, however, was that she also seemingly lost the ability to look toward her left to look for things or perhaps lost the concept of "left" entirely. In order to find something that she though was present but couldn't see (because it was on her left), she would spin around to the right until she came all the way around to what she was looking for. Further, when eating she would finish half of her food, spin around to the right, eat half more, spin to the right, eat half more, and so on. In order to assist her with makeup, the doctors attempted to use a video cameral and television screen instead of a mirror, so that the left side of her face (which she could not see in a mirror) now appeared on her right. This totally freaked her out, though, and she cried out "Take it away!" causing the doctors to not explore the matter any further. "

14:29 / 27.03.03

Just to say that I neglected to properly credit the above-posted lyrics, which are from Hedwig and the Angry Inch.

14:32 / 27.03.03

Something I've always wanted to know is whether kids growing up and learning to write in languages that are written right to left, ie Hebrew, are more likely to be left-handed. It would make sense, as lefties are at a natural disadvantage in left-to-right languages because their hand covers up what they've just written, and the majority of left-handed people I've known have pretty messy handwriting. Not that there's anything wrong with messy handwriting and plenty of right-handed people have have it too, but I was wondering if kids don't already choose "hands" by the time they learn to write.

14:54 / 27.03.03

I'm pretty sure that handedness is set at quite a young age, and moreover that it is exhibited in other apes which do very little writing. People with unattractive handwriting might have some evolutionary disadvantage though. Is one's handedness inherited?

And is there a proper word for 'handedness'?

14:59 / 27.03.03

I don't think that could be the case, Lolita, since "true" handedness appears to have a strong genetic component, though it appears to be difficult to control for in experiments (parents "forcing" their children to be of similar handedness as themselves and suchlike).

Some factoids here

I'm right-handed, but when people watch me write with a pen, they always tell me I hold it like a lefty. Now, perhaps I just need to be taught how to a hold a pen properly, or maybe I was forced by nuns at an early age to write right. In either case, I often suffer from left-right confusion, though only when someone says something like "look at that freak, over there, on your right." I'll invariably look left. In my internal dialogue, however, I have no such confusion.

15:28 / 27.03.03

Oh God, me too with the confusion. In fact I always thought "Your Other Left" would be a good band name. It's what my family always said to bust on me when I messed up left and right. Making that L out of the index and thumb of my left hand has saved me more times than you can count. That said, when I see someone writing on TV or in real life with their left hand, I always recognize it immediately.

15:41 / 27.03.03

my mum is nominally right-handed but is essentially ambidextrous in pretty much every other aspect other than writing - and she is absolutely diabolical when it comes to distinguising left from right. when she took her driving test she drew a big 'L' and 'R' on each hand (yes, I kid ye not!) in case she got muddled through nerves. I have no idea whether the two are related, or perhaps she's just really dippy when it comes to left and right, hehe.

Whisky Priestess

15:44 / 27.03.03

Isn't left/right confusion often to do with dyspraxia?

16:19 / 27.03.03

must...resist..temptation to...diagnose...myself.... with...developmental disorder....augh.....

16:39 / 27.03.03

I'm sure I've told this story before... but hey, I don't have that many stories so recycling's bound to happen. But anyway, it has always been a part of family lore that I started to write with my left hand & this not being acceptable to my paleo-father, I was "trained" to write with my right hand. I don't remember this & I only half-believed this until I saw him switching crayons on my niece (me reincarnated, only I'm not dead)... from her left to her right hand. And I believe, lightly slapping her left hand & saying bad! That was not a good day for Dad, let me tell you. So I think I'm a "tempered" left-hander... I'm a lot less mad about this than I used to be. I mean, whatever, I am who I am.

01:09 / 28.03.03

Hand preference starts really early - my niece, at the ripe old age of 2 and a half, was a very determined lefty.

I consider myself to be a right-hander, but am pretty ambidextrous from years of labwork and early musical instrument training... I can use scissors happily with either hand and write with my left, but the writing is at about the 8 year old stage as far as consistency and neatness.

I may have started out as a lefty - I don't have any memories of being forced one way or the other, but I've discovered that my left eye is the dominant one (makes archery interesting!). I don't know how common it is for that sort of mismatch to occur?

06:25 / 28.03.03

Once when on acid I couldn't figure out why people had two eyes, you know because it didn't make sense to me ,(symmetry wise at least, why if people had half a nose and half a mouth running along the central symmetry line of the face they wouldn't have half an eye at each side? But then you know I couldn't tell the difference between far away and close up that well either. Did acid lobotomise me, or is it just a strange fixation with symmetry, you decide! (I'm just back from work and too tired)

10:16 / 28.03.03

It is true that if you are dyspraxic the way your brain connects up is generally a bit muddled and odd. Generally all the people I know with dyspraxia have big troubles with left and right, but most of them are also dyslexic.

I know quite a lot of people (myself included) with preference mismatches, but again, most of them have been diagnosed with some developmental delay thing at some point in time.

Has anyone come across evidence to support the idea that babies in the womb lie with the side that is dominant so that has more chance to move and develop?

Persephone - that happened to my Mum at school and she's still mad about it.

12:30 / 28.03.03

happened to my Mum too, but as soon as she left (

) school she went back to leftedness.
Pointless trivia: 'Sinister' means left handed 'Dextrous' means right.(thus the 2000AD characters Sinister and Dexter) We inherit our cultural bias for right handedness from the Romans.

13:20 / 28.03.03

Okay, how do I tell which eye is dominant? I have a tendency to mix up my contacts, as readers of my blog can attest.

13:25 / 28.03.03

More pointless trivia: in heraldry, dexter refers to the right-hand side of the shield-bearer, that is the left side of the shield as you look at it, and is the more honourable side of the coats of arms - so much so that 'sinister' charges such as bends and bars sinister were used to denote illegitimacy.

13:26 / 28.03.03

Todd - with both eyes open extend your arm and 'ring' an object with finger and thumb. Then close one eye and if the object jumps out of the ring, the eye you've got closed is the dominant one.