Lefties don't have it easy in this world. It is littered with invisible obstacles. Even race tracks, which seem such equitable venues for human competition, favor people who are right-side dominant. Since their right legs can take longer strides than their left ones, they turn more easily through leftward curves. Thus most runners finish faster going counterclockwise than clockwise and eventually the former became the right way around.
Furthermore it's no coincidence that "right" - which comes from the Anglo-Saxon word riht meaning "correct" - is also the word for the dominant hand of most people. "Left" comes from the Anglo-Saxon lyft, meaning weak or useless. Such connotations can be observed in many languages: Words for right tend to be synonyms for things like justice, strength, and skill, while those for left signify clumsiness, awkwardness, wrong, and evil.
Though negative feelings toward left-handed people have abounded throughout history, and in some places continue to do so today, we southpaws have still managed to do well for ourselves. Lefties include an impressive list of high achievers, and are hugely overrepresented among Nobel Prize winners, U.S. Presidents, and famous artists, athletes, and academics. Lefties are often credited with having "a wider scope of thinking" which enables greater abstraction. But what does that mean? What does handedness have to do with thought? And why are there lefties - or righties for that matter - in the first place?
Handedness results from asymmetry in the brain. The region that controls language and speech is located in the left brain hemisphere in most people. Since speech and dexterity require similar types of finesse, it is assumed that these skills are controlled together (by the left hemisphere). Since that hemisphere is more neurally connected to the right side of the body, the right side usually ends up possessing more finely tuned motor skills.
The brains of lefties, though, are not simply mirror images of those of right-handed people. The division of labor in their brains tends to be much less cut-and-dry. For example, speech is controlled by the left hemisphere of about half of left-handed people's brains, just like it is for everyone else, while dexterity seems to be controlled on the right side. Another fourth of lefties' brains divide speech processing between the two hemispheres, probably handling dexterity on both sides as well.
This ambiguity may imply more connectivity between different brain regions, engendering abstract thinking (as well as higher rates of mental illnesses like schizophrenia).
What causes the brain to sometimes switch up or mix around? There is no clear consensus on the matter, just several interesting hypotheses. First of all, left-handedness is barely genetic. A child of two left-handed parents has only a 26% chance of being left-handed: higher than the 1-in-10 incidence in the general population, but not that much higher. Some scientists think left-handedness is caused by more testosterone than usual flooding the fetus at a critical moment during gestation. This would explain the higher incidence of left-handedness in males than females, and it could also relate to the putative evidence of a correlation between handedness and sexual orientation. However, the way in which testosterone influences brain lateralization isn't established.
One major evolutionary advantage of being left-handed is greater prowess in combat. Studies have shown that lefties are over-represented among violent or war-torn populations, implying that they do better in battle. This could have to do with the unexpected or unusual style in which they are biologically bound to fight, but it also points to heightened spatial awareness as well as greater ambidexterity. Considering how much of human history has been spent in combat, the following question comes to mind: Why isn't everybody left-handed, or better still, ambidextrous? Why is the right-handed model the prevalent one? Therein lies the ultimate unanswered question when it comes to handedness.
Please pass this article along to any lefties you know: We tend to be more interested in discussions of handedness than anybody else!
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