Research Into Left-Handedness And Its Effects
See our page of current lefty research and resultsThere has been a huge amount of research done into various aspects of left-handedness, often without much in the way of clear conclusions. We will be using this section to provide articles and links for you to see and to let you know of current research that is going on that you could possibly participate in.
If you are involved in research into left-handedness or its effects, please let us know and we will include details in this section.
We have a lot more information to go in this section, so check it again next time you visit us.
New age of genius led by left-handers! (Mar 2002)
![]() | Evolution may be in the process of delivering a new age of genius and creativity, with left-handers leading the way. Professor Chris McManus of University College, London has been researching the subject and is about to publish a new book called Right Hand, Left Hand. He is convinced that the proportion of left-handers is rising and left-handed people as a group have historically produced an above-average quota of high achievers.
He says that left-handers' brains are structured differently in a way that widens their range of abilities and the genes that determine left-handedness also govern development of the language centres of the brain. |
In Britain, around 13% of men and 11% of women are now left-handed, compared to just 3% of those born before 1910. There are a number of factors driving this increase:
- Left-handers were severely discriminated against during the 18th and 19th centuries and it was often "beaten out" of people
- In adulthood, left-handers were often shunned by society, resulting in fewer marrying and reproducing
- As discrimination was reduced in the 20th century, the number of natural left-handers who stayed left-handed increased
- The rising age of motherhood contributed as, statistically, older mothers are more likely to give birth to left-handed children
The professor says that the increase could produce a corresponding intellectual advance and a leap in the number of mathematical, sporting or artistic geniuses.
Unfortunately, it is not all good news for left-handers. They tend to be over-represented at both ends of the intellectual scale and as well as geniuses the group also produces a disproportionately high number of those with learning handicaps. There have been suggestions of links between left-handedness and dyslexia, stuttering and child autism among others.
Left-Handers Club comment...
We have had a lot of anecdotal evidence of an increasing proportion of left-handers among young children and our correspondence with members supports the view that left-handers are over-represented at both the top and bottom of the learning and achievement scale.
Now that left-handedness is not actively discouraged and young left-handers can obtain basic tools like pens and scissors to allow them to learn and express themselves in their own direction, most stay as left-handers and do not have their naturally creative advantages interfered with.
We have known Professor McManus and his work for the past 10 years or so and we will give further comment on his current project when the results are published in full. We also hope that he will give us some further background and personal comments that we can pass on to our members.
The Left-Handers Club is planning a major series of surveys this year which will aim to discover which activities and occupations groups left-handers are over- and under-represented in and the factors that affect this. We will be producing further information on this and asking for assistance very soon.
Ambidextrous tendencies may mean better memory
Source: New Scientist, 22 October 2001, James Randerson
Having a close left-handed relative makes right-handers better at remembering events than those from exclusively right-handed families, new research suggests. There is a downside, however, as members of these ambidextrous families may be relatively impaired in their ability to recall facts.
According to the study, having a left-handed sibling or parent means the organisation of your brain is intermediate between a pure 'lefty' and a pure 'righty'.
Specifically, Stephen Christman and Ruth Propper at the University of Toledo, Ohio claim that people with 'lefties' in the family have a larger corpus callosum - the connection between the brain hemispheres. This makes you better at certain memory tasks, but worse at others, they believe.
Two types of memories are involved. Episodic memories are those with a context that is separate from the information itself - for example, where you parked your car or where you left your keys. Semantic memories on the other hand are things 'you just know', such as the dates of the First World War or the recipe for apple pie.
Filling the gaps
The researchers showed 180 right-handed subjects lists of words. Some of this group was asked to recall as many of the words as possible once the list had been taken away. This tests episodic memory because the subjects have to remember the words they were taught.
Others from the group were given fragments of words with a letter missing and asked to fill in the gaps. This semantic test simply relies on knowing how the correct word should be spelt. Subjects with close left-handed relatives did better at the first 'remember' task, but worse at the second 'know' task.
"The key difference is not whether you are right handed, but whether you are strongly or weakly handed," explains Christman.
Making the connection
A definitive explanation for the results is still some way off, says Christman. But he suspects that it might involve the roles that different brain hemispheres play in memory. He believes the information itself tends to be stored in the left hemisphere, while the place and time context resides in the right.
Both these components will be useful in episodic memories, so he suspects that people with a large corpus callosum linking their hemispheres - such as those from more ambidextrous families - will do better at these tasks. Semantic memory requires only one hemisphere, so it may be that those with fewer connections between the hemispheres have less interference and perform better.
Chris McManus, an expert in handedness at University College London, agrees that people with left-handed relatives have a brain that is "slightly more like that of a left-hander".
But he is sceptical about Christman's explanation. The link between a weak-handedness and a large corpus callosum is "distinctly controversial", he says.
Journal reference: Neuropsychology (vol 15 (4)
Ambidextrous: The worst of both worlds?
Leading British psychiatrist Prof. Tim Crow believes he can show that ambidextrous children are less intelligent than their peers - and his theory could even shed light on schizophrenia.
Unlike our closest genetic relative the chimp - who is truly ambidextrous - humans tend to heavily favour one hand and struggle to perform simple tasks with the less favoured. Prof. Crow, of the University Oxford, believes this difference could be crucial to the evolution of humankind around 137,000 years ago. The development of a division in function between the left and right sides of the brain - which result in our tendency to be right or left-handed - was a major factor in our leap from Homo erectus to Homo sapiens.
"Handedness is the key dimension of human cerebral function," says crow. "People who are truly ambidextrous are slower to develop verbal and non-verbal skills. It's the predictor of both reading difficulties at the age of 16 and psychosis".
For his study, Crow analysed data taken from 12,770 1 year old children taken in 1969 as part of the UK National Child Development Study. The children had been tested for hand preference, verbal, reading and mathematical ability. The test immediately resolved the age-old argument over whether right or left-handers are more intelligent : the answer is that there is absolutely no difference between them. What was startling was how badly ambidextrous people performed in the study - they did dramatically worse in all 3 tests. Youngsters who were extremely right or left-handed also tended to do poorly, but not as badly as the ambidextrous children.
"There seems to be an optimum level of handedness at which we perform best, although we are not sure what that is" said Crow. "Most of the variation in intelligence is to do with the degree of handedness in the child."
Crow is aware these results may anger the parents of ambidextrous children, but he stresses that more research is needed to interpret the results fully. "The problem is that intelligence is a nebulous concept" he says. "These children may simply be late developers. Or they may be developing in a completely different way."
Crow says that the gene responsible for encouraging specialist functions in one side of the brain, such as handedness, is what allows us to develop advanced skills, and without it the language centre of the brain would not have been able to develop. It is this development of language that differentiates us from the animals, and Crow's research continues into pinpointing exactly which gene or group of genes this is.
The consequences of this could be controversial, since they raise the possibility that we may one day be able to manipulate the very genetic material which makes us human. However, although this gene may set us apart from the apes there appears to be a cost. Crow believes that the same genetic changes that allowed the development of language by creating imbalance in the brain also created the potential for schizophrenia. "It is the price that Homo sapiens pay for language" he says.

Comments 77
I am not advocating against these studies but there needs to be research into the effects of left-handed children forced to abandon their natural hand dominance.
The abuses of children over the subject of hand preference needs to stop.
Child abuse is not tolerated for any reason except in this one area and in this area unlike most there is little means for escape.
When I read comments here, I realized I share a lot of similarities with many people and felt really happy that I was not alone sailing in rough sea. For example, having two solutions to simple problems and then struggling to decide which one is the correct. I am 24 now, but I still face it. So, I started training myself to think how other's think so that my answers match to theirs and I am still working on that part.
But, the most difficult thing that I face is understanding/relating oral instructions like (being part of some rapid conversations, giving directions to someone ) and another is imaginary counting. Like, suppose I have to add two four digits numbers, I take time to imagine them and then while generating results even at the units place, I again lose track of the number, re-imagine and perform the task. It takes a long time and affects my speed. SO, the only work around I have for it is, I write down the number and perform it.
I would like to know if anyone is facing a similar problem?, is it specific to Lefties?, is it some kind of disease and can I overcome it with practice of certain things?. Like, I have tried to solve many problems mentally, but no much useful effect I have seen.
Someone please reply.
Thanks and have a nice day.
Have you found other people have had this happen.
Really would like to know.
Your's Sincerly
Mrs Carol Costello
What was special about US?
Thank you
Regards
It was difficult at first, but is now second-handed.
I'm retired and into neuroplasticity and neurobics.
In the same class last year with a smaller number of students, half were left-handed.
The left-handed students today were really happy to be in the majority!
I've been reading about links to the vestibular system (really important in music) and the corpus callosum (above). Male musicians tend to have larger corpus callosums than the rest of the population. Females just have relatively larger corpus callosums in proportion to the rest of the brain. Not different in female musicians. So I'm fascinated by the research into left-handedness. Thank you!
Now, I'm almost sixteen, and I've become a sort-of famous Instagram artist, and I couldn't be happier that I made the choice to embrace all of my little lefty quirks.
My little sister is left-handed as well (which is weird since neither of my parents is) and I hope that she learns to embrace all the little oddities that come with dominantly using her left hand.
Maybe one day.
But now i still find it difficult to grab things easily . I quickly forget things.
Anyway out pls.. Looking forward to your responce tru my email address. Thanks...
Sister: Right handed, above average intelligence, but not as smart as my Bro or I.
Mother: Ambidextrous, not very smart in comparison, average intelligence if not below.
How do we not know those from earlier history who were forced into rightyness, didnt cause mental and emotional conflict, including learning obedience, and getting reinforced for listening to authority?
Geniuses are those that go against authority in one way or another. By definition geniuses are people that actually think "more", average people just believe they think, or don't think at all.
Average are those by its own definition, follows the crowd, these people arent world changers.
Think about it.
I could go on and intertwine 10s of ideas, facts and theories, but I'll resist.
Lefties are only smarter because we're always against the tide, cant create new without conflict, just like cant study a species without changing them.
i'm a final year u.g physiotherapy student and i am currently searching for a project regarding the difference in kinematics of right handed v/s left handed population or the relation b/w being a lefty and having problem with some instruments.
can someone help me in finding refrences for either?
I'm a southpaw, and I'm not good at remembering. I'm better at knowing.
My own struggles to determine which hand to use for different tasks (ex. write left-handed, almost all else right-handed, mouse the computer w/both hands, etc.) have led me to wonder if there are many of us out there for whom a dominant hand did not emerge. Are there studies about such issues? I would be very interested to learn of others who had to choose, and may have had to revise, which hand to use.
Thank you!
Connie
I am also left handed. I use my left hand to write, and I eat with my right hand. I never knew being left handed means you are more intelligent but this will give me huge self esteem from now on.
I am really bad at aiming, can't use any of my hands in it successfully. Sometimes I throw with my left some times my right, undetermined.
I forget a lot. I have a very selective memory. This is hard for someone who works in the academia.
I respond to verbal conversations really slowly. It can take days to find the right answer to a conversation.
Kind regards
Julie
Request. How possible can you assist me to publish my Article on this academic dissertation regarding left-handers and right-handers?
I have contacted you direct by email to see if we can do something with this research
I have a son who is ambidextrous and has trouble remembering and comprehending in school he is 9. Are there techniques that can help him to learn better. He tries so hard and really gets frustrated that he does not remember.
I was thinking that both sides of his brain is working to solve problems and that it makes it hard for him to remember. Am I crazy in thinking this or is their research that may support this. I would like to give his teachers and myself some resources to help him.
Thank you,
Tim Bertrand
My mom is right handed, but my dad his dad and i are all left handed..
And i hate how in elementary they made me use scissors right handed and to this day it still feels akward.
I have spoken to a few people and where they first started going to school, (they were left handed)
but the teacher forced them to right with there right hand.. My handwriting; people say it looks like doctors handwriting, I think it looks like chicken scratch..
When i write my hand is kinda bent and i turn my paper sideways so its easier to write, i write at a slant kinda.. Am i the only one whos tried to play a DS and tried drawing with my left hand and not being able to move the character because the arrows are on the left handed side and not the right?...
And i actually love reading and writing.. And i play an insturment.
Also so i dont know if it was just me, but i got told all left handers do this when they first started school..
They would write there name backwards?? Like mine would still come out like CALLIE but i just wrote from
Right to left, but it still came out normal CALLIE
Also 0000
Im also a lefty, and have set myself on fire twice and electrocuted myself three times!(always an accicient i hasten to add) mmm maybe im researching the wrong thing! :)
Any replies will be greatfully recieved
Mother of a 5 year old Leftie Boy.... He is in his second year of school( his birthday falls in August and he started school just as he was 4) and teachers have identified he is very intelligent. Acedemically he is extremely bright..! However he doesn't seem too keen on writing and expresses this daily..! He told me he is sad because he is always last to finish his writing tasks in school etc..! His daddy and I have spoken to his Teacher and asked te obvious question... Are you aware he is Left Handed..! They are..! Out next question was to ask what support he is receiving to enable him to write in a
Way that assists him.. For example : tilting the paper to the right when writing..we were told nothing needs to be done other than a little extra time to keep up with his handwriting..! We feel that this is not enough and need guidance / tips from anyone out there with similar issues..! Advice would be greatly appreciated..!
This should be taught in pre-school on up!!!!
Generally, I have found right handed teachers need help in knowing how to train the left handers in their classes.
Im your opposite. I can write with the left, and am better with the right hand than my friends are with their left. I shoot hoops with my right, but play tennis with my left hand. I can bowl with both of my hands but cant even handle a pair of scissors in the left hand. As for the patterns idk, im not even 40 yet, but the learning part is the same for me. I hate it when teachers make me do sth i dont want to do. I feel more comfortable at hearing and memorizing than talking and messing up. As ironic as it may sound, especially because of my last comment, i was best at english and also corrected teachers. History and geography are the most difficult for me, but i was still first of class, even in PE. I was like the girl who can do anything
I write with my right hand. But can write a little with left.. better than average for right handers. I noticed in the past I played golf left handed, tennis right. I shoot left handed.. don't do that any more.. Cricket left handed. baseball left handed. I am 64 now so really don't do much of those things any more. I sew and knit, crochet etc. But cannot read patterns. They confuse me. I can see a shirt and know how to put a collar on by looking at it but cannot follow pattern instructions to do so. I can see how things are done and work out a way to do them. During the years I have gone to classes to learn how to do things but not participated, just watched. It was really frustrating because the teachers always want you to get on with it and 'give in a try.' I tried to explain but they didn't 'get it.' I am self taught in many things because that is how it had to be. I would say I am above average intelligence and it drove parents and teachers crazy,, Anyway.. anyone out there like me? I only met one and it was my father.
maybe you have this problem sorted by now, but I was in an identical situation with my son. His dyslexia was not identified until he went to college. he found a coloured acetate sheet helped him read. he explained this as on white backgrounds the letters seemed to fidget about which made focussing a slow painfull process. He seems to have adapted well as an adult and is an avid reader now. The biggest problem he had was lack of school support which drained all his confidence. Focus on all his good points and boost his confidence wherever you can. He will find his way in the world. good luck and best wishes :)
He has a son of his own now, who is showing at 4 months he a lefty too :)
Please allow me to present another theory--ambidextrous people are constant wafflers. Because their brain is in a perpetual state of 'split-decision' this makes the ADULTS around these children PSYCHOTIC because adults are always demanding that children "pick a side" or "make a decision NOW" or "do it or else." These attitudes and their lack of patience--like how doctors have always been with Autistics--is FAR MORE DAMAGING THAN BEING AMBIDEXTROUS. Autistic children often suffer from a form of post traumatic stress disorder due to abuse via "the Village." It is more common and pervasive than the disorders themselves.
Cure the Village's ill-thinking, and the Autism and brain damage WILL take care of themselves. If this were untrue, then so many Mom's wouldn't have figured out how incredibly intelligent their Autistic children are--even if they are retarded. Doctors simply locked these children up and experimented on them. If you'd like to know exactly how intelligent 'mentally retarded Autistics' are--as Sue Rubin. She has quite a story to tell.
She is exremely smart appears ot be ambiudexter and multi tasker.
I am technical, educated and statistically knowledgable person. All the studies according to my reading points out the data collection at ages 8 and 16.
I believe the resarchers are missing the boat by not studying the kids eralier then age 8. It is my belief that the results they are achieving that shows ambiudexters to be brain dead. They are too late to discover the smartness in these kids, why; at age 8 kids are alread fallen behind of an average kid due to environment and lack of knowledge from parents and teachers to give them the correct support in advanced learning. At age 7 they are baranded as ADD or ADHD or AD without HD. This happened to my oldest son. When child study cented professor tested him his IQ was way above average and he was diagnosed with AD without HD. It turned out the drug they gave him did not work. His pediatrician was at all time disagreement with the diagnoses. Later on it turn out tomato was part of his problem (thanks to my wife who discovered it) We home schooled him.
He does not have alot of friends but he is a quick learner and out of 4500 students and teachers at his high school he was the oly one self thought and programmed an industrial robot and won state championship two years in row. He was behind at school at age 8 and untill we home schooled him.
So, all the scientists who are out there studiying a population and using data provided by school counsellers are not wrong but chosing a wrong population.
The analysis of data is, to do something with the data not to point us what is or where the problem is. We should use data to improve.
Younger children under 7-8 should be the focus and we should develop a program that should take these ambiudexter kida to a next level of advancement not to their discurragement by we not knowing what to do. They desrve it, they are your and my kids.
My grandson is now 4 years old and joining at kindergarden school. He writes by left hand and loves to active his left hand in most of time.He uses his right hand in daily activities only in presser by parents.I am worry about his left hand writing. Hence,shall I try to right hand writing instead of left hand writing or leave it to write by left hand, which is best ? kindly could you suggest me by email .
Thanks and regards,
N . Mahat
A 15 yr old or longer study showed between heterosexual males, homosexual males and females that the corpos collosum of the female was the largest, the homosexual male the smallest and the homosexual male somewhere in between.
This may account for the fact that women can multi task paying bills with playing/supervising the children while their husbands can only do left brained work, like accounting or whatever single focus they do.
Are there any studies that relate size of corpus collosum with ambidextrousness in females; or males; or monkeys who are ambidextrous.
Ths from a lifetime natural athlete, female, ambitdextrous, only one in the family or even left handed), creative, multiasked, color coding, natural gps for locating materials in my office without files and cabinets, also a scholarly post grad researcher seeking colleagues and answers and more questions.
Clarification:
Study showed corpus collosum of heterosexual males was the smallest (cc= integrator of both sides of brain, linear and creative).
The size of corpus collosum that was the largest was of females.
The mid-sided corpus collosum was found in homosexual males.
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