A person who is left-handed primarily uses his or her left hand, more so than the right hand; a left-hander will probably use the left hand for tasks such as personal care, cooking, and so on. Writing is not as precise an indicator of handedness as it might seem. A better determination of left-handedness results when the differentiation between an individual's major motor activities versus fine or small muscle motor activities is employed. Thus the applications of one's left-hand for eating, writing and similar fine motor activities would be differentiated from major motor activities such as throwing a ball or swinging a bat, etc. While there are numerous individuals who use their left hand for fine motor activities, there is a much smaller group of people who are "total lefties" i.e. do both fine and major activities with their left hand.
In 1977, a study suggested that approximately 15 to 25% of the adult population was left-handed. Studies indicate that left-handedness is more common in males than females. Left-handedness, in comparison to the general population, also appears to occur more frequently in identical twins, and several groups of neurologically disordered individuals (such as people suffering from epilepsy, Down's Syndrome, autism, mental retardation and dyslexia). Statistically, the identical twin of a left-handed person has a 76% chance of being left-handed, identifying the cause(s) as partly genetic and partly environmental. Also, people of South Asian, Eastern European and Southeast Asian descent are more likely to be left-handed than any other ethnic group in the world, while people of Western European, Northern European, and African descent are less likely to be left-handed.
Causes of left-handedness
- See main article at handedness.
- Hand orientation is developed in unborn children, most commonly determined by observing which hand is predominantly licked or held close to the mouth. Current genetic research suggest there is a genetic factor involved.
- In 2007, researchers discovered LRRTM1, the first gene linked to increased odds of being left-handed. The researchers also claim that possessing this gene slightly raises the risk of psychotic mental illnesses such as schizophrenia.
- Long-term impairment of the right hand: People with long-term impairment of the right hand are more likely to become left-handed, even after their right hand heals. Such long term impairment is defined as 6 months or more.
- Testosterone: Exposure to higher rates of testosterone before birth can lead to a left-handed child. This is the Geschwind theory, named after the neurologist who proposed it, Norman Geschwind. It suggests that variations in levels of testosterone during pregnancy shape the development of the fetal brain. Testosterone suppresses the growth of the left hemisphere and so more neurons migrate to the right hemisphere. The highly developed right hemisphere is now better suited to function as the center of language and handedness. The fetus is more likely to become left-handed, since the right hemisphere controls the left half of the body. The theory goes on to tie the exposure to higher levels of testosterone and the resultant right-hemisphere dominance to auto-immune disorders, learning disorders, dyslexia, and stuttering, as well as increased spatial ability.
- Ultrasound theory: Ultrasound scans may affect the brain of unborn children, causing higher rates of left-handedness in mothers who have ultrasound scans compared to those who do not. This is probably based on a few studies  where this relation is studied. In one of these the authors claim that "...we found a possible association between routine ultrasonography in utero and subsequent non-right handedness among children in primary school." However later in the same article the authors state that "Thus the association ... may be due to chance" and "The result was not significant, suggesting that the study had insufficient statistical power to resolve the relationship between ultrasonography and subsequent left handedness in the child"
Social stigma and repression of left-handedness
Negative associations of left-handedness in language
There are many colloquial terms used to refer to a left-handed person. Some are just slang or jargon words (in some parts of the English-speaking word 'cack-handed' is just a synonym for left-handed, though see also below), while others may be offensive or demeaning, either in context or in origin. In more technical contexts, 'sinistral' may be used in place of 'left-handed' and 'sinistrality' in place of 'left-handedness'. Both of these technical terms derive from sinister, a Latin word meaning 'left'.
Some left-handed people consider themselves oppressed, even to the point of prejudice. Etymology often lends weight to the argument:
In many European languages, "right" is not only a synonym for correctness, but also stands for authority and justice: German and Dutch recht, French droit, Spanish derecho; in most Slavic languages the root prav is used in words carrying meanings of correctness or justice. Being right-handed has also historically been thought of as being skilful: the Latin word for right-handed is "dexter", as in dexterity; indeed, the Spanish term diestro means both "right-handed" and "skilful". In Irish, "deas" means "right side" and "nice". "Ciotóg" is the left hand and is related to "ciotach" meaning "awkward".
Meanwhile, the English word "sinister" comes from the Latin word "sinister,-tra,-trum", which originally meant "left" but took on meanings of "evil" or "unlucky" by the Classical Latin era. Alternatively, "sinister" comes from the Latin word sinus meaning "pocket": a traditional Roman toga had only one pocket, located on the left side for the convenience of a right-handed wearer. The contemporary Italian word sinistra has both meanings of sinister and left. The Spanish siniestra has both, too, although the 'left' meaning is less common and is usually expressed by 'izquierda,' a Basque word. The German word for left is links, and the adjective link in German has the meaning of "slyly" or "devious", while linken means "to betray" or "to cheat" (sb.).
The left side is often associated with awkwardness and clumsiness, as shown in the French gauche, and adroit, droit meaning right, and adroit meaning skilled. German links and linkisch and the Dutch expression "twee linkerhanden hebben" ("to have two left hands", which means being clumsy). As these are all very old words/phrases, they support theories indicating that the predominance of right-handedness is an extremely old phenomenon. In Portuguese, the most common word for left-handed person, canhoto, was once used to identify the devil, and canhestro, a related word, means "clumsy".
In ancient China, the left has been the "bad" side. The adjective "left" (左 Mandarin: zuǒ) means "improper" or "out of accord". For instance, the phrase "left path" (左道 Mandarin: zuǒdao) stands for illegal or immoral means. In some parts of China, some adults can still remember suffering for the "crime" (with suitable traumatic punishments) of not learning to be right-handed in both primary and secondary schools, as well as in some "keeping-good-face" families.
In Norwegian, the expression venstrehåndsarbeid (left-hand work) means "something that is done in a sloppy or unsatisfactory way". Additionally, one of the Norwegian words for left-handed, "keivhendt", comes from Norwegian words meaning wrong handed or not straight handed.
The Hungarian word balfácán means twit. (Bal means left and fácán is for pheasant.) Other synonims are balfék and balek. However all these are euphemistic versions of the original vulgar word balfasz, combining "bal" and the vulgar name of the male genitals fasz.
In England, left-handed people are sometimes referred to as 'cackhanded', referencing their supposedly clumsy nature.
Even the word "ambidexterity" reflects the bias. Its intended meaning is, "skillful on both sides". However, since it keeps the Latin root "dexter", which means "right", it ends up conveying the idea of being "right-handed at both sides". This bias is also apparent in the lesser-known antonym "ambisinistrous", which means "clumsy on both sides" and derives from the Latin root "sinister."
In Esperanto, the word "left" is rendered maldekstro, literally meaning "opposite of right." (The prefix mal-, does not mean "bad", but rather "opposite"; in fact, "generous" translates as malavara, meaning "opposite of greedy.") A left-handed person is maldekstrulo.
A left-handed individual may be known as a southpaw, particularly in a sports context. It is widely accepted that the term originated in the United States, in the game of baseball. Ballparks are often designed so that the batter is facing east, in order that the afternoon or evening sun does not shine in his eyes. This means that left-handed pitchers are throwing from the south side. The first use of the term is credited to Finley Peter Dunne. However, the Oxford English Dictionary lists a non-baseball citation for "south paw", meaning a punch with the left hand, as early as 1848, just three years after the first organized baseball game.
In boxing, someone who boxes left-handed is frequently referred to as southpaw. The term is also used to refer to a stance in which the boxer places his right foot in front of his left, so it is possible for a right-handed boxer to box with a southpaw stance. Most boxers, southpaw or otherwise, tend to train with sparring partners who adopt a right-handed stance, which gives southpaws an advantage.
Accessibility of implements and skills
Left-handed people are sometimes placed at a disadvantage by the prevalence of right handed tools in society. Many tools and devices are designed to be comfortably used with the right hand. For example, (right-handed) scissors, a very common tool, are arranged so that the line being cut along can be seen by a right-handed user, but is obscured to a left-handed user. Furthermore, the handles are often molded in a way that is difficult for a left-hander to hold, and extensive use in such cases can lead to varying levels of discomfort. Most importantly, the scissoring or shearing action - how the blades work together (how they are attached at the pivot) - operates correctly for a right-hander, but a left-hander will tend to force the blades apart rather than shearing the target substance. (This is especially awkward if the scissors are loose and/or blunt.) Left-handed scissors do exist; until they have tried cutting with some, many right-handed people do not believe the difficulties experienced by left-handers using right-handed scissors.
The computer mouse is sometimes made to fit the right hand better. Many computer installations have the mouse placed on the right side, making it awkward for left handers to use without moving the mouse to the other side of the keyboard. Some mouse drivers and operating systems allow the user to reconfigure the mouse buttons to reverse their functions. However, being left-handed does not always mean the person uses the mouse on a computer with the left hand; many left-handers can use the mouse right-handed because they learned it that way from the start. Some lefties have claimed that this gives them an advantage because they can use the mouse with their non-dominant hand, leaving their left to do tasks such as taking notes and such uninterrupted.
While European-style kitchen knives are symmetrical, Japanese kitchen knives have the cutting edge ground asymmetrically, with ratios ranging from 70-30 for the average chef's knife, to 90-10 for professional sushi chef knives; left-handed models are rare, and usually must be specially ordered or custom made. 
The lack of left-handed tools and machines in many workplaces is not only a nuisance to many left-handers, but has actually placed them at peril. One example is the band saw, whose standard design is convenient for right-handers but encourages left-handers to pass their arms dangerously close to the cutting blade with every pass of the saw.  In fact, some factories have installed left-handed equipment after successful class-action lawsuits on behalf of left-handed employees. 
Many well-intentioned companies have manufactured products with left-handers in mind, but have still failed to meet left-handers' needs. For instance, many companies have produced "left-handed scissors" by simply inverting the scissors' handles, making the grip work for the left-hander. Unfortunately, for scissors to function in a truly left-handed manner, their blades must also be mirror-inverted, without which the left-hander is forced to make a "blind cut" because the blade obscures the paper from view. Fiskars is one company that has produced truly left-handed scissors, inverting both the blades and the handles.
Left-handed adaptations have even bridged the world of music; guitars are often made especially for lefties, and there have even been inverted pianos where the deepest notes correspond to the rightmost keys instead of the leftmost.
Left-handed golf clubs were one of the earlier, and well-accepted, manifestations of a special version of an implement.
It can be difficult for left-handed children to learn to write if the teacher does not take the student's left-handedness into account. When properly done, left-handed writing is a mirror image to that of the right-hander, making the teaching process confusing for the teacher (if right-handed) of a left-handed student. The result is that many left-handed people learn to write with their hand curled around the pen so that it can meet the paper at the same angle as the right hander, rather than simply tilt the paper the opposite way. Once this habit is formed, it is difficult to break. This curling of the hand results in the heel of the palm being placed behind the writing, forcing the writer to lift it off the paper and making the grip even more awkward. When the left hand is held correctly, it is below the writing, as is typical for right-handers.
However, left-handed people who speak Arabic, Persian, Urdu and Hebrew or any other right to left language, do not have the same difficulties with writing. The right to left nature of these languages prevents left-handers from running their hand on the ink as happens with left to right languages.
For these reasons, many left-handed people have poor handwriting. Styles of writing in which the relative thicknesses of the up- and down-strokes (as made by a right-handed person) are considered important are virtually impossible to produce correctly for a leftie; left-handed nibs, which look most peculiar as they are curved at the end, were produced, though many lefties consider them awkward. Fortunately, the decline in the use of the fountain-pen in general, in favour of pen types which produce a line whose thickness is independent of the direction of movement, have rendered this matter largely academic, except among enthusiasts of calligraphy.
The vast majority of firearms are designed for right-handed shooters, with the operating handle, magazine release, and/or safety mechanisms set up for manipulation by the right hand, and fired cartridge cases ejected to the right. Also, scopes and sights may be mounted in such a way as to require the shooter to place the rifle against his right shoulder. A left-handed shooter must either purchase a left-handed firearm (which are manufactured in smaller numbers and are generally more expensive and/or harder to obtain), shoot a right-handed gun left-handed (which presents certain difficulties, such as the controls being improperly located for them or shell cases being ejected towards their body), or learn to shoot right-handed (which may pose additional problems, primarily that of ocular dominance). Fortunately for left-handed people, modern guns feature more ambidextrous or right/left-handed reversible operating parts than their predecessors. Bullpup rifles are particularly problematic for lefties unless they can be reconfigured, since empty shells would be ejected fast and straight into the shooters face and cheek potentially causing injury. Lever action and pump action firearms present fewer difficulties for lefties than bolt action weapons do.
An example of an ambidextrous weapon is the FN P90, which has the magazine inserted into the top of the gun. The shells are ejected out of the bottom, making the gun usable by either right or left handed marksmen.
Left-handedness and intelligence
Some studies argue a correlation between left-handedness and creativity/intelligence.
In his book Right-Hand, Left-Hand, Chris McManus of University College London, argues 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 centers of the brain.
In Britain, a study in the 1970s found that around 11% of men and women aged 15-24 were left-handed, compared to just 3% in the 55-64 age category. McManus suggests a number of factors that may be driving this increase:
- Left-handers suffered severe prejudice 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 prejudice declined 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.
McManus says that the increase could produce a corresponding intellectual advance and a leap in the number of mathematical, sporting, or artistic geniuses.
In 2006, researchers at Lafayette College and Johns Hopkins University in a study found that left-handed men are 15% richer than right-handed men for those who attended college, and 26% richer if they graduated. The wage difference is still unexplainable and does not appear to apply to women.
Statistics show that older people are less likely to be left-handed than their younger counterparts — the percentages of left-handed people sharply drop off with increased age. In the U.S., 12% of 20 year olds are left-handed, while only 5% of 50 year olds and less than 1% of people over 80 are.
A study (no longer deemed credible) published in 1991 claimed that these statistics indicate that left-handed peoples' lifespans are shorter than those of their right-handed counterparts by as much as 9 years. The authors suggested that this may be the result of left-handed people being more likely to die in accidents as a result of their "affliction", which renders them clumsier and ill-equipped to survive in a right-handed world.
According to The Left-Hander Syndrome most people were only forced to write with their right hand and allowed to continue being left handed in most other respects indicating that the decline in older left-handers is not from being forced or switching in later life.
Left-handers in Popular Culture
There are many left-handers in sports; however, a written rule in polo states that one must not hold a stick in his or her left arm. There are very few left-handed professionals in polo; all are required to use their right hand. Jai-Alai is another sport where left-handed play is forbidden.
In field hockey, right-handed play is effectively required (though not explicitly so) because one rule states that the ball cannot be played with the back of the stick and left hand sticks are not allowed. The reason for this is because when attempting to tackle the opponents stick, the left hander would have to go through his/her legs, while another specifies that the stick be flat on its left side, which would be the "natural" side for a right-handed player, but when playing with the stick in one hand (playing reverse), this can give an advantage back to the left-handers. Having all players play with the same handedness is essential to keeping hockey a non-contact sport: a left-hander and a right-hander competing for the ball would tend to collide. All-left-hander matches are possible, but rare. Despite this rarity in left-handed play, a surprising number of high level players are left-handed. It is likely that this is because left-handers have their dominant hand at the top of the stick where it may provide an advantage for stick control.
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Being left-handed can be an advantage in many sports. For example, in fencing, a right-handed fencer might be more accustomed to facing another right-handed fencer simply because being right-handed is more common. A left-handed fencer might also be more accustomed to facing a right-handed opponent for the same reasons. Therefore, when a right-handed fencer faces a left-handed opponent, the right-hander is not as used to fighting a left-hander as the left-hander is used to fighting a right-hander, causing a noticeable advantage. The same advantage may be present for most one-on-one or face-to-face sporting events.
Baseball is particularly suited to left-handed players for several reasons: left-handed batters are already a step or two closer to first base in their batter's box before they even hit the ball and are more likely to beat out close plays, although a left-handed hitter faces third base and has to pivot before running to first. Many baseball parks have shorter right field fences which gives left-handed sluggers a few more home runs that would otherwise be outs. And finally, most pitchers are right-handed which gives the left-handed hitter a better angle to see the ball and causes curve and sliding pitches to move towards them, rather than away. That is why a good switch hitter is considered valuable. Also, it is generally preferred (but not required) that first-basemen be left-handed to give them a better tagging angle on pick-off moves. Left-handed fielders cannot play third base, shortstop, or second base, however, because the throwing position towards first base is awkward for a lefty. Catchers are virtually always right-handed as well, because it is difficult to throw to third base in an attempt to catch a base-stealer if you are left-handed. The only career catcher to ever throw with his left hand was Jack Clements, who caught for 17 years in the 19th century. A left-handed pitcher naturally faces toward first base, and thus can easily keep an eye on a runner trying to steal second. However, a right-handed pitcher has a more natural body movement in throwing the ball towards first base, when attempting to pick off the runner. One player, Charlie Grimm, or "Jolly Cholly," was known as "baseball's only left-handed banjo player"--rare indeed when one considers how difficult it is to play most stringed musical instruments left-handed.
In football (soccer), left-handed players are often more skilled at playing with the left foot (though being left-handed does not necessarily result in being left-footed), which makes them valuable as they can play better on the left side of the field than right-handed players. Interestingly, in the sport of ice hockey, there are many more left-handed shooters. When shooting left, the player's left hand is in the middle of the stick, and the right hand is at the top of the stick. When skating fast, or stretching to reach a far away puck, a player will often use only the top hand on the stick. Many right-dominant players shoot left-handed, allowing them to use their dominant hand when wielding the stick one-handed. The majority of goaltenders also catch with their left hand.
In tennis, left-handers impart spin on the ball that is opposite of that which a right hander would hit. As a result, right-handed players (who are accustomed to playing right handers) have difficulty dealing with a left-hander's shots which curve in a direction opposite to what they are accustomed to facing. Rafael Nadal, despite being right-handed, plays left-handed tennis after being encouraged to do so by his coach for this very reason.
In American football, the most famous left handed players are usually quarterbacks, such as Kenny Stabler, Michael Vick, Steve Young, Boomer Esiason, Matt Leinart, Mark Brunell, and Jim Zorn. Vick may be an exception though, since he is normally right handed, but throws with his left, despite there being many left handed quarterbacks who have had much NFL success.
In basketball, left handed players have a distinct advantage on both ends of the court. On defense, it easier to play against a right-handed player since the defender typical angles the left side of his body towards the dribbler to both force him to dribble with his left hand, and to raise his own left hand in the event of a jumpshot. Conversely if that offensive player is left handed, the standard defensive stance would favor them as they are not being forced to use their weaker hand. In fact, dribbling with the left hand is a highly valued skill in basketball for this very reason. When shooting, since the defender will typically raise his left hand to attempt the block the shot (since his left hand will be closer to the shooter's right-handed shot) a left-handed shooter will have more room to see the basket and attempt the shot.
In water polo, being left-handed allows a player to have an easier time shooting from the right side of the field, as having their shooting hand towards the middle of the field allows them to whip the ball around the keeper and into the upper left corner, a shot which a right-hander in the same position would find impossible. Also, when driving into the center from the right side, a left-handed player can take a dry pass and immediately shoot, whereas a right-handed player would require a wet pass and have to try and chip the goalie on a pop shot. This is why many teams like to have left-handed players, and why they tend to only play on the right (right-handed players have all similar advantages on the left side of the pool).
Boxing appears to be something of an exception to the rule that being a southpaw confers an advantage. Until Karl Mildenberger fought Muhammad Ali in 1966, there had not been a southpaw challenger for the heavyweight title since James J. Corbett, aka "Gentleman Jim" in 1892, and there have only been three southpaw heavyweight title holders since then: Michael Moorer, Corrie Sanders, and the current WBA heavyweight champion Ruslan Chagaev. However, it is worth distinguishing between the southpaw stance and being left-handed, because some trainers will train a naturally left-handed boxer to fight in an orthodox stance, not merely for convenience but because there may be an advantage in having the jab delivered with the stronger hand. Hence a number of boxers who fought in an orthodox stance may have been converted left-handers.
In cricket, left-handed players have thrived over the years. Many technically sound batsmen have been left-handed. As of mid 2006, each and every of the Test playing nations have at least one left-handed batsman in their side. One of the reasons for this is that having a mix of right and left-handers tends to disrupt the bowler's accuracy, because when both a right-handed batsman and a left-handed batsman are batting, the bowler must adjust the line he is bowling when the batsmen change ends. Some famous left-handed cricketers include yesteryear greats like Graeme Pollock, Allan Border, David Gower, Gary Sobers, Wasim Akram and Mike Whitney; and contemporary greats Brian Lara, Saeed Anwar, Sourav Ganguly, Sanath Jayasuriya, Adam Gilchrist, Graeme Smith, Mike Hussey and Matthew Hayden. It is also well-known that Sachin Tendulkar and Darren Gough both write left-handed. However, many of these players are actually right-handed but bat left-handed.
In ten-pin bowling, left-handed bowlers often need to buy bowling shoes with a sliding sole on the right shoe (the right foot is the one used for release), unless both right and left shoes have sliding soles. There is a stereotype that left-handers start from the outside of the lane and do a stroker style release. Left-handed bowlers include Rafael Nepomuceno, Earl Anthony, Parker Bohn III, Jason Couch and Patrick Allen.
Minor sports where left-handedness is a significant advantage include Eton Fives, where the buttress is on the left, the ideal serve placing the ball at the bottom corner - almost impossible for a right-handed player to reach. Another is Real (Royal) Tennis, in which the serve along the penthouse is far easier with the left hand than with the right.
In video games, the Nintendo character Link is often left-handed. Though in the Super Nintendo release, he alternates hands, but this is due to sprite mirroring. In The Legend of Zelda: The Minish Cap, however, Link returns to alternately holding his weapon in the right or the left hand, depending on his orientation. At the beginning of the Four Swords Plus (Four Swords Adventures) manga, Link is referred to as the “left-handed hero” after defeating pirates that were raiding a Hylian town. In addition, Link's figurine description in Wind Waker lists his "manual preference" as left. However, in the animated TV series, Link is right-handed. In the Wii version of Twilight Princess, Link is right-handed, but this was done as a result of the mirroring of the game's map, to better fit the game's control scheme. Because of this, the maps in the Wii version have been mirrored. However, in the game's official artwork he is shown holding his sword in his left hand. In the GameCube version, Link remains left-handed, since the game keeps a traditional control scheme.
Studies show that left-handedness does not necessarily correspond with "left-sidedness" (such as using your left foot to kick with), though most left-handed people tend to have "left-sidedness". The same effect holds with ocular dominance. It has also been found that people have dominant sides of the body, such as the eye, foot, and ear. Many people believe that firing a rifle depends on hand dominance; however, in actuality it depends on eye dominance.
Possible effects in humans on thinking
There are many theories on how being left-handed affects the way a person thinks. One theory divides left- and right-handed thinkers into two camps: visual simultaneous vs. linear sequential.
According to this theory, right-handed people are thought to process information using a "linear sequential" method in which one thread must complete its processing before the next thread can be started.
Left-handed persons are thought to process information using a "visual simultaneous" method in which several threads can be processed simultaneously. Another way to view this is such: Suppose there were one thousand pieces of popcorn and one of them was colored pink. The right-handed person — using the linear sequential processing style — would look at the popcorn one at a time until they encountered the pink one. The left-handed person would spread out the pieces of popcorn and visually look at all of them to find the one that was pink. A side effect of these differing styles of processing is that right handed persons need to complete one task before they can start the next. Left-handed people, by contrast, are capable and comfortable switching between tasks. This seems to suggest that left-handed people have an excellent ability to multi-task, and anecdotal evidence suggests that there are more creative stems due to this ability to multi-task.
Right-handed people process information using "analysis", which is the method of solving a problem by breaking it down to its pieces and analyzing the pieces one at a time. By contrast, left-handed people process information using "synthesis", which is the method of solving a problem by looking at the whole and trying to use pattern-matching to solve the problem. 
The hypothesis that left-handed people are predisposed to visual-based thought has been validated by a variety of evidence. In the 2004 book Brains that work a little bit differently, researchers Allen D. Bragdon and David Gamon, Ph.D., briefly described some of the current research on handedness and its significance. "Handedness researchers Coren and Clare Porac have shown that left-handed university students are more likely to major in visually-based, as opposed to language-based subjects. Another sample of 103 art students found an astounding 47 percent were left- or mixed-handed." [page 76]
Ultimately, being left-handed is not an all-or-nothing situation. The processing styles operate on a continuum where some people are more visual-simultaneous and others are more linear-sequential.
- Chirality (chemistry)
- Chirality (mathematics)
- Chirality (physics)
- The Tale of Cross-eyed Lefty from Tula and the Steel Flea
- Geschwind-Galaburda Hypothesis
- Situs inversus
- Handedness and sexual orientation
- ↑ Hardyck, C., & Petrinovich, L. F. (1977). "Left-handedness", Psychological Bulletin, 84, 385–404.
- ↑ Raymond, M.; Pontier, D.; Dufour, A.; and Pape, M. (1996). |Frequency-dependent maintenance of left-handedness in humans", Proceedings of the Royal Society of London, B, 263, 1627-1633
- ↑ Twinning Facts - National Organization of Mothers of Twins Clubs, Inc.. Accessed June 2006.
- ↑ Cantor, J. M.; Klassen, P. E.; Dickey, R.; Christensen, B. K.; Kuban, M. E.; Blak, T.; Williams, N. S.; & Blanchard, R. (2005). PDF (136 KiB) Archives of Sexual Behavior, 34, 447–459.
- ↑ Schachter, S. C.; Boulton, A.; Manoach, D.; O'Connor, M.; Weintraub, S.; Blume, H.; & Schomer D. L. (1995). "Handedness in patients with intractable epilepsy: Correlations with side of temporal lobectomy and gender", Journal of Epilepsy, 8, 190–192.
- ↑ Batheja, M., & McManus, I. C. (1985). "Handedness in the mentally handicapped", Developmental Medicine and Child Neurology, 27, 63–68.
- ↑ Cornish, K. M., & McManus, I. C. (1996). "Hand preference and hand skill in children with autism", Journal of Autism and Developmental Disorders, 26, 597–609.
- ↑ Grouios, G.; Sakadami, N.; Poderi, A.; & Alevriadou, A. (1999). "Excess of non-right handedness among individuals with intellectual disability: Experimental evidence and possible explanations", Journal of Intellectual Disability Research, 43, 306–313.
- ↑ Ask Yahoo!: Why am I right-handed, but my brother is left-handed? Accessed June 2006.
- ↑ Gene for left-handedness is found , http://news.bbc.co.uk/2/hi/health/6923577.stm, BBC, 31 July 2007
- ↑ Watkins M (1995). Creation of the Sinister: Biological Contributions to Left-handedness Accessed May 2007.
- ↑ “Routine ultrasonography in utero and subsequent handedness and neurological development”, K.A. Salvesen, L.J. Vatten, S.H. Eik-Nes, K. Hugdahl, L.S. Bakketeig, British Medical Journal, Vol. 307, 1993,159-64.
- ↑ “Routine ultrasound screening in pregnancy and children’s subsequent handedness.” H. Kieler, O. Axelsson, B. Haglund, S. Nilsson, K.A. Salvesen, Early Human Development, Vol. 50, 1998, 233-45.
- ↑ yourDictionary Word of the Day: sinistral. Accessed June 2006.
- ↑ "My Left Foot," The Kingdom, 24 July, 2003. Accessed June 2006.
- ↑ Etimología de izquierda, deChile.com. Accessed June 2006. (Spanish)
- ↑ , your dictionary.com, November 28, 2003.
- ↑ . Accessed August 2006.
- ↑ Morris, Evan (1995). Word detective research. Accessed June 2006.
- ↑ "How to Succeed at Knife-Sharpening Without Losing a Thumb" New York Times, September 23, 2006. Accessed September 23, 2006.
- ↑ References needed
- ↑ references needed
- ↑ http://www.lefthandedpiano.co.uk/about.html
- ↑ Right-Hand, Left-Hand official website Accessed June 2006.
- ↑ Steele, James & Mays, Simon (1995). New findings on the frequency of left- and right-handedness in mediaeval Britain.
- ↑ "Sinister and Rich: The evidence that lefties earn more", by Joel Waldfogel. Appeared in Slate on August 16, 2006.
- ↑ LEFT HANDERS EARLY DEATH MYSTERY, 5 articles thereon. Accessed September 2006.
- ↑ [The Left-Hander Syndrome: The Causes and Consequences of Left-Handedness 1993]
- ↑ Rule A.1(c), PDF, Federation of International Polo, 2002. Accessed July 7, 2006.
- ↑ Rule 9.5, PDF, The International Hockey Federation, 2006. Accessed July 7, 2006.
- ↑ Rule 4.6, PDF, The International Hockey Federation, 2006. Accessed July 7, 2006.
- ↑ http://www.anthonyhempell.com/papers/tetrad/visual.html
- ↑ http://www.giftedservices.com.au/visualthinking.html
- ↑ http://www.arty4ever.com/right/brain.htm
- ↑ http://painting.about.com/library/blpaint/blrightbrain.htm
- ↑ http://painting.about.com/od/rightleftbrain/a/Right_Brain.htm
- ↑ http://www.amazon.com/dp/0916410676/
- Lefties Have The Advantage In Adversarial Situations, ScienceDaily, April 14, 2006.
- Science Creative Quarterly's overview of some of the genetic underpinnings of left-handedness
- Quirks & Quarks June 10, 2006 (CBC radio documentary on left-handedness including interviews with four scientists holding different views on the determinants of handedness)
- A left-handed senior citizen recalls the emotional torment he faced at a New York public school in the 1920's. (Audio slideshow)
- Famous Left-Handers
- Left-Handers Day - the official left-handers club site.
-  Association of left handers in India.
- Schwartz, Alyssa (2005). "Lefties face increased breast cancer risk," C-Health News, 30 September.
- Scans may 'cause brain changes', BBC News.
- prolevaky.cz - left handed resources in Czech and slovak language
- www.left-hand.org - The Left-Handed Page
Template:Handar:أعسر bg:Левичар ca:Esquerrà cs:Levák da:Venstrehåndet de:Linkshändereo:Maldekstruloid:Kidal it:Mancinismo is:Örvhentur he:שמאליות hu:Balkezesség nl:Linkshandigheidno:Venstrehendthetsk:Ľavák sr:Леворукост fi:Vasenkätisyys sv:Vänsterhänthetuk:Шульга Association of left handers India [www.lefthanders.org]
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