Left Handed - Right Handed

John Gorst john at gorst.demon.co.uk
Sat Mar 28 10:12:01 EST 1998


I am currently doing course work for 'A-Level' Biology. 

The course work is based on the 'learning curve' in humans. The experiment will
basically be that the subject has to draw around a quite complex shape using one
hand then the other - then repeat them both viewing it in a mirror. The subject
will be timed when doing this. They will repeat each possible combination 6
times.

I am expecting the following results:-
There will be very little improvement in the times when the subjects are using
their right hand viewing it normally.
There will be a considerable improvement when they do it with their left hand,
when viewing it normally.
There will be a continual improvement when they do the test using a mirror - the
'curve' will continue when they swop hands.

I have to find biological reasoning for these improvements.
I am going to say:-

- there is little improvement in the right hand as the neurological pathways
controlling it are fully developed.

- there is an improvement in the left hand as the neurological links as being
developed. Although the left hand will not get as good as the right hand in such
a short length of time as there has to be cell growth to do this (I had the idea
that the myelin sheath was not fully developed around the neurones controlling
the left hand therefore the control of it is not as fast and not as accurate due
to slower propergation of signals and interference - is this correct???)

- there will be a continual improvement when doing the test in a mirror as there
is only ONE part of the brain which controls eye to hand co-ordination.
Therefore there will be a continuation in the 'curve' between the left and right
hands when viewing through a mirror as the neurological pathways are being
established benefit the use of both hands.

Could you give me your view on the above reasoning.
What I need is some definite biology behind 'building neurological pathways' as
this is a very vague statement. Also what part of the brain controls eye to hand
coordination? There part of the brain which 'flips' the image from the eye
vertically - does a similar thing happen when you do a activity looking at it
through a mirror but on a horizontal plane?

Note:- when I say left and right hand.... for the purpose of this experiment I
am going to use major and minor hand but I forgot to use these expressions in
this article.

Thanks for any help

(could you please post to the newsgroup and via e-mail as my ISP currently has a
12 hour backlog on their news and is possibly loosing quite a lot of articles -
but I will be keeping an eye of this NG)

--
JG
john at gorst.demon.co.uk



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