The Naked Scientists

The Naked Scientists Forum

Author Topic: Why Are Most people RIGHT Handed ? and other dextrous orientated queries !  (Read 778 times)

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Dearest Academic Authors Of Great Contributioness,

Why are most people right handed ?

why ?

why are there some left handed people ?

I am right handed but eat left handed ...why ?



Are there other issues more subtle that are differences between right and left handed people ?


Do other animals display right and left handedness too ?




whajafink  ?


I could not be bothered to post a piccy of a right handed person so i chose a lettuce instead !...that's a right handed lettuce by the way !!


hugs and shmishes


mwah mwah mwah


neil
xxxxx

Right left right left right left !!   halt !!










 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4699
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
This question has intrigued me for years, and I have a theory based on a few flimsy facts.

In my youth, about 10% of my cohort were lefties, but the proportion has been rising and teachers tell me it's now over 20%. That's an awful lot of genetics in one generation!

As a student I noticed that several mathematics students were lefties, but very few history undergrads. Some chums produced an intuitive "spectrum" with maths on the left and history on the right, and found a remarkable correlation between mathematical/analytical course content and lefthandedness of students.

Many composers are/were lefties but few musicians.

Sinistral CEOs earn on average 15% more than dextrals.

There is a weak correlation between lefthandedness and speech defects.

Now nature doesn't generally do things at the 10% level. Genetics tends to be 50% or "very rare". So here's my theory:

Human language, and bipedal locomotion, require a huge amount of brain power. No other species can throw a missile accurately, and chucking an apple core and a ball of paper across the office and into the wastebin one after another without conscious thought, is completely beyond other apes. I think that half of us are born ambidextrous, but half have a genetic defect that, in order to cope with language, locomotion and dexterity (well chosen word!) the brain sacrifices fine control of the left hand. So given that half of us cannot be lefthanded, society evolved around righthandedness.

The lucky 50% born-ambis have a choice. Generally, more than half will choose to go with the flow but some will choose to be different and may gain some advantage, possibly at the expense of some speech development, by seeing the world from a slightly different point of view. Hence, as society becomes more tolerant of variation, the number of voluntary lefties has increased towards 25%. Once you have acquired some basic childhood  "dexterities" with screw threads, scissors, etc., a lefty gets used to trying different approaches to a problem and making hypothetical leaps as well as following the book, hence developing a flair for analysis and creativity.   

The only remaining puzzle is why all the Simpsons characters are lefthanded, apart from the customers at Ned's Leftorium.
 
The following users thanked this post: neilep

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
This question has intrigued me for years, and I have a theory based on a few flimsy facts.

In my youth, about 10% of my cohort were lefties, but the proportion has been rising and teachers tell me it's now over 20%. That's an awful lot of genetics in one generation!

As a student I noticed that several mathematics students were lefties, but very few history undergrads. Some chums produced an intuitive "spectrum" with maths on the left and history on the right, and found a remarkable correlation between mathematical/analytical course content and lefthandedness of students.

Many composers are/were lefties but few musicians.

Sinistral CEOs earn on average 15% more than dextrals.

There is a weak correlation between lefthandedness and speech defects.

Now nature doesn't generally do things at the 10% level. Genetics tends to be 50% or "very rare". So here's my theory:

Human language, and bipedal locomotion, require a huge amount of brain power. No other species can throw a missile accurately, and chucking an apple core and a ball of paper across the office and into the wastebin one after another without conscious thought, is completely beyond other apes. I think that half of us are born ambidextrous, but half have a genetic defect that, in order to cope with language, locomotion and dexterity (well chosen word!) the brain sacrifices fine control of the left hand. So given that half of us cannot be lefthanded, society evolved around righthandedness.

The lucky 50% born-ambis have a choice. Generally, more than half will choose to go with the flow but some will choose to be different and may gain some advantage, possibly at the expense of some speech development, by seeing the world from a slightly different point of view. Hence, as society becomes more tolerant of variation, the number of voluntary lefties has increased towards 25%. Once you have acquired some basic childhood  "dexterities" with screw threads, scissors, etc., a lefty gets used to trying different approaches to a problem and making hypothetical leaps as well as following the book, hence developing a flair for analysis and creativity.   

The only remaining puzzle is why all the Simpsons characters are lefthanded, apart from the customers at Ned's Leftorium.

Thank ewe so much for this wonderful reply.

Why should their be a growth in left handedness I wonder ?....could it be ongoing ?   maybe it has something to do with the reversal of the earths poles ! (joke)

Aren't most composers musicians too ?

Did someone actually do a study of the left/right handedness of CEO's ?   

Thank ewe again, really appreciate your reply


 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4699
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile


Why should their be a growth in left handedness I wonder ?....could it be ongoing ?   maybe it has something to do with the reversal of the earths poles ! (joke)
I think it's a trend towards the 25% expected value, resulting from a relaxation of primary school teaching. In my youth, lefthandeness was treated as a correctable affliction and kids were given remedial handwriting classes. I wonder if this, along with the observation of sinistral scientists, might account for the infamous "doctors' handwriting"?

Quote
Aren't most composers musicians too ?
Multidimensional answer (a posh name for a fudge) coming up! Pretty well all professional musicians play keyboard (or xylophone in the case of percussionists) to some extent, much as all office workers can use a computer. Those who make their living by composing or conducting rather than playing will certainly need to be proficient if not concert-standard keyboarders, and although the left hand part is frequently less complex than the right, you need a lot of left dexterity (there must be a better word!) to get beyond Grade 5. You occasionally come across lefthanded folk fiddlers but a leftie orchestral bowman will poke someone's eye out or end up fencing with the adjacent cellist. Woodwind and saxophone definitely need two good hands but brass instruments and the guitar family are traditionally righthanded - with the weird exception of the French horn, and froghorn players are notoriously weird anyway. Of the four Beatles, the one who wrote most of the songs is lefthanded, along with Beethoven, Rachmaninoff, at least one Bach, possibly Mozart, and a host of modern composers and arrangers. 

Quote
Did someone actually do a study of the left/right handedness of CEO's ?
Yes. Can't find the reference but it was in the late 1990s, around the time they discovered that the starting salary for male graduates was correlated with height, not class of degree.   

One historic anomaly is that Henry Boyle, who invented the standard general anesthetic machine, was lefthanded and all such equipment has been back-to-front ever since. The wouldn't be a problem except for the fact that when two surgeons are operating on one patient, there's a clear advantage if one is lefthanded, so the number of sinistral anesthetists is probably lower than the expectation value.
« Last Edit: 17/09/2016 23:42:58 by alancalverd »
 
The following users thanked this post: neilep

Offline chris

  • Neilep Level Member
  • ******
  • Posts: 5337
  • Thanked: 65 times
  • The Naked Scientist
    • View Profile
    • The Naked Scientists
 
The following users thanked this post: neilep

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Thank ewe very  much alancalverd and chris for your responses. Fascinating about the back to front anaesthetic machines !!
« Last Edit: 04/10/2016 18:43:55 by neilep »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Chris, Any other left handed progeny ?
 

Offline cheryl j

  • Neilep Level Member
  • ******
  • Posts: 1460
  • Thanked: 1 times
    • View Profile
There are some genes that are adventitious but only when a minority of the population possess them . Think baseball. It's an advantage to be left handed but only if most of your opponents aren't. In genetics , it's called frequency dependent selection.  The trait will never become widespread, but never disappears either - if it's too common, it's stops being an advantage, but when it becomes rare it starts being one again.
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums