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Chimpanzees Shed New Light on Hand Preference
An anonymous reader writes "'Language skills are associated with the left side of the brain, and many scientists have said early humans developed a preference for their right hands when they acquired speech,' but Emory University's Yerkes National Primate Research Center has a new study that links hand preference to the motor skills area of the brain rather than the language part of the brain. 'That means lefties have probably been around much longer than believed -- at least 5 million years, when scientists say humans and apes branched on the primate family tree. And evolution has purposely kept them.'"
if lefties has a better channce of using the brain's motor neurons, then why did evolution choose to have 2/3 righties in the chimp population. doesn't it goes against darwin's theory?
i fact just about every creature in nature and everything in nature has "handedness"
only a "scientist" could attribute this to something recent like language skills.
http://slashdot.org/~GuyFawkes/journal
You Sinistromanualist, you...
More seriously the, errr, granparent post is referring to this happening to his grandfather. Minus the beating, this was still happening to me when I was at school in the eighties (UK). An English teacher made a concerted effort to force me to be right-handed, and it completely messed up my writing. You can see a clear difference between the schoolbooks I had before her 'teaching', and those I wrote afterwards.
For the worse, of course.
Cheers,
Ian
it's a neurological deficit called dyspraxia. Read it up and talk to her about it.
This was my first reaction too. Why the hell would hand preference be connected to the language part of the brain?
Martin
It'd be intersting to know what percentage of Slashdot users are left handed, my guess is it's more than the population average.
While at Georgia Tech, I was amazed at how many left handed people their were in all my classes. Being left-handed myself, I had always noticed that the percentage around me approached approximately what wikipedia says is the average, or 10-13%. I'd say at Tech it was more like 30-40%.
For the most part they were all a bunch o toolbags, but luckily I'm in good company with Ned Flanders...
I've been thinking of starting a lawsuit for reparations for all the discrimination myself and all my left-handed bretheren have suffered over the years. Society's first attempt to make me feel bad was those damn right-handed scissors in Kindergarden, and it hasn't stopped. We're talking decades of trauma hear, and this didn't happen to my ancestors. Hell, just think about where the attached pen is next time you sign a credit card reciept.
Equal rights for Lefties! Affirmative action for lefties! Welfare for Lefties! State funded concubines for Lefties! Handedness as a criteria for college admissions!
One strange thing I've noticed when teaching and attending Emergency Medical Services (read 'ambulance service') classes is that there are a higher number of lefties then the general population.
At the station in my town 4 out of the 9 EMS workers are left handed.
There's no place like
I am left-handed and I can say I do take advantage of it. I play volleyball and it always takes some adjusting until the opponent starts to block my left hand instead of my right. Playing squash, opponent often let me play mostly forhand because they don't realise my weak side is the other one.
And quite obviously, this is even true for two left-handed opponents playing against each other. With majority of my opponents being right-handed, I myself am taken bu surprise when I meet left-handed opponent.
Obvously, this advantage is lesser in repeated encounters and lesser when there are more left-handed people around.
Obviously there is no disadvantage for being left handed, why should there be a selection against it?
Could you please forward that insight to Logitech ?
Crivens! I kicked meself in me own heid!
Interesting article though I disagree with the statement about LH persons being less analytical.
I'm a third gen lefty (tree: PGM, F, myself). My eldest son fell from near my side of the family tree and he (now 6) has only ceased to be ambidexterous in the last two months. He went to the dark side and uses his right hand to throw and write. Still bats and kicks left however so maybe he'll make it to the major leagues yet. Still holding out hope for the newborn daughter.
Anyway, I'm PhD physicist, my Dad (LH) is a very talented mechanical designer/engineer. Grandmother was a puzzle wizard. If you look at PhD level scientists you will find more than the nominal 10% LH... which does not support the "less analytical" assertion. On the other hand (pun?) perhaps we LH are less analytical but in return we are given better gifts to see analytic tasks as in a more wholistic light. Maybe this is why Maxwell's Equations, classical E&M, the Standard Model Lagrangian and GR are as beautiful as Sunday Afternoon by Seurat or as magnificent as DaVinci's David to me.
I'm a leftie. The reason I think left handness exists is specialisation. Darwinian theory doesn't mean we will all be the same exact highly optimised beings. What happens if the environment changes? Evolution would not be able to react fast enough. Instead sucessful groups of our ancestors, the ones which survived, emerged from the jungle and ultimately produced us, had group members with different strengths, different abilities. It's like any game, for example it red alert or d&d. If you only have spell casters in a party, or one type of unit in an attack, you will not be as successful as a mixed group.
As a christian, I strongly agree.
It's ridiculous to suppose that God would have created a whole universe and then expected us to restrict our examination of it to a short list of statements.
And in Victorian times, everyone used to think the same way; the business of a scientist(*) was to admire, analyse, and better appreciate God's creation. Then the ****ing Evangelicals came along and it all went straight to heck.
(*)Except Frankenstein.
Whence? Hence. Whither? Thither.
using the left hand exclusively for output functions & the right for input does result in better health, even if the underlying cause is unknown...same with dietary laws, even the caste system, anti-sodomy laws, monogamy...it's only a kludge if there's something better, ie: washing, but then that's not an option in a desert environment;-)
;-)
in a pre-literate, pre-sanitary world, the only way to promulgate useful knowledge is to codify it into mnemonic narratives, enforced by the cloak of the supernatural...ie: why religion was invented
The list goes on here.
While helping my girlfriend with her lab on the common Fiddler crab (Uca pugilator) I decided to do some side-research of my own*. I found that approximately 1/3rd of Fiddler crabs in our population (of about 20) were left-handed (in that their left claw was freakin' huge). This would lead credence to an earlier post talking about handedness being a surprise to rivals.
It is interesting to see, however, that the Scientific American article covering the same subject seemed to focus more on the study whose results found similarites in the limbic system asymmetry between primates. The handedness study (which of course waters down easier for the average person) seemed to be second fiddle.
By the way, the actual studies are found here (in 300-500KB PDFs):
Asymmetries in the Hippocampus and Amygdala of Chimpanzees
Handedness in Chimpanzees (Pan troglodytes) Is Associated With Asymmetries of the Primary Motor Cortex but Not With Homologous Language Areas
* I had previously determined that the bisque turned out a bit stringy and that scampi was preferred. This, sadly, derailed the other, more "important" research.
Small potatoes make the steak look bigger.
But chimp research would have to null out the contributions to handedness that might be made by any number of OTHER differences in brain development between humans and the rest of the primates before these scientists, let alone a bunch of
- The timeline of human brain development from birth to adolescence is hardly one of linear increases in all capabilities and is not the same as chimps
- the LACK of parity between LH and RH dominant individuals is complex: the numbers are not evenly distributed but that is obscured, as serveral posters reported, by cultural enforcers that mask biologicaly determined behavior. We might even be seeing the reports of apparent intellectual advantages in a few lefties because our culture has beaten the lefthandedness out of a larger subset of the population with only the more gifted and adaptable surviving the brainwashing.
...These areas have a definite correlation to handedness as a right-handed person has a 97% chance of having these speech structures on the left versus the right while in a left-handed person has a 50-50 chance of this (if my neuroanatomy is correct)....[bloodredsun's comment] is particularly interesting since it implies there are yet other dimensions to the asymmetry between LR and RH dominance, these are not distributions of capability that are anatomically just mirror images of each other but distinctly different wiring.- I have not read every comment but so far there is no report of data correlating extent of corpus collosum [CC:the bridge between L and R hemispheres. nearest analog to a computer bus you will find in brain anatomy] to handedness. The CC is [if memory serves] is better developed in women than men ON AVERAGE and women [perhaps as a consequence] have [on average] less rigid specialization of functions to particular brain regions. This is why [on average] women recover more fully from strokes then men do.
- someone probably trotted out the stat that lefties have more accidents and I just missed it. Its a whole other debate about whether that is due to strong tendencies to put the saftey/kill-switch/brakes/etc on dangerous equipment where a RH person would expect them or due to other considerations but its not likely to be attributable to language skills...differences between LH and RH persons that don't stem from language either support or don't repute the findings of the article so I guess this one is a point for the sciencists.
- Is there any study or known correlation between handedness and [_]dyslexia, [_]ADD or ADHD, [_]Stuttering, [_] other developmental anomalies, e.g. autism?
But, of course, I have my anecdotes too;)My mom reports that she was probably a lefty but growing up in the 30's in a Missouri village where the dogs barked in German and you were either a Luthern or a Methodist, she had that bad habit beaten out of her. One of my boys writes [illegibly] with his left hand but throws [and I mean quite athletcally: he's an ultimate frisby player] righty.
and PLEASE, if you can't read or react in an informed and rational way concerning the general fact that there are differences between men and women, please exit the conversation NOW!.
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
...definitely has its advantages if you're used to using a mouse with your right hand. I can surf and take notes at the same time. Also, I'm better at finding the really ripe fruit.
Then what was I watching for the 3 years of my PhD!
You're right in that pre-frontal lobotomies (a la "one flew over the cuckoo's nest") are no longer done but you will find that temporal lobectomies are common for medically-refractive temporal lobe seizures (espec. due to hippocampal sclerosis pathology) and even entire hemispheres (a hemispherotomy) for Rassmussens syndrome are still performed.
On a lighter note, the wonderfully named "Multiple SubPial Transections" has been shown to be very effective for Landau-Kleffner syndrome (where sufferers have extreme difficulty in speech), so you must be very relieved!
As far as I know the number of left-handed in the Middle East (and Asia for that matter) is equivalent to the number in the west, so I don't think this has got anything to do with the direction of writing. Is seems to be mostly a coincidence. An interesting point is that all people "read" pictures the same way - left to right - no matter how they are used to reading letters.
-- A good compromise leaves everyone mad. --Calvin and Hobbes
Pick up any child development book (like any college book) and it will tell you that whatever side you lie on in the womb determines if you are left or right handed. And it makes perfect sense, too. If you are lying on your left (as many obviously do) your right arm is free to move and start developing motor skills. And if you lie on the right, you have to use your left arm to move all about. And there is really nothing you can to about it. That's why natural selection hasn't just "threaded" them out, because there has been no way to. Just because your parent's are both lefties dosen't mean you will be, because you prob won't.
There are some studies that link brain lateralization to personality in birds and mamals, which provides an explanation of the survival benefits of having both left and right handed members in a species: http://www.abc.net.au/catalyst/stories/s1139554.ht m/
(Ask yourself - who do the marmosets remind you of??)
Someone else did a game theory analysis of how predation could lead to lateral specialisation in prey as a survival strategy, but I don't have the link.
For the profoundly right lateralized(~LH), you might appreciate these marmosets also:
http://www.rathergood.com/moon_song/