Ancient History

Studies of skeletal remains indicate a preference for the right hand even among ancient hominins. In fact, of the 54 hominins discovered, only four appear to be left-handed. Scientists are not entirely convinced that handedness has to do with genetics or wiring in the brain, as previously thought. Some researchers think hand preference may originate in the spinal cord.

Recent History

For hundreds of years, the mystery behind left-handedness led to a stigma against the minority. In the 14th and 15th centuries, bias stemmed from religion. For most religions, the right hand is considered 'godly.' Therefore, dominant use of the left hand, especially for eating and writing, was considered unholy. Not only that, but with left-handedness being a bit of an anomaly, most lefties were written off as witches or conjurers of the devil, and subsequently burned at the stake. Fun!

But it's not all bad. Left-handed sword fighters found themselves at an advantage in combat since most fighters had only practiced with other righties.

In later centuries, the stigma continued, but theories were being developed. Teachers continued to punish students for writing with their left hand, but the act was viewed as unmannerly rather than a sign of outright evil.

The Science

The biological cause of left-handedness can be traced to both genetic and environmental factors, though not much is known or confirmed about the influence of either. There are, of course, a number of theories.

One is that mothers aged 40 and above are more likely to give birth to a left-handed baby. Birth stress is more common in older women and corresponds directly to left-handedness.

Another is the Right Shift Theory. This theory is primarily genetically-based and points to the presence of a particular gene (RS+) among the majority of the population, which has caused a 'right shift' when it comes to hand preference. Left-handed people are not said to have a "left-handed gene," but simply lack the RS+ gene, rendering them indifferent when it comes to hand choice. For years, this was the widely accepted theory, though recent research suggests the cause is more complex.

Yet another, more recent theory, brings us back to the influence of the spinal cord. There is some evidence to prove that during a fetus' development, "gene activity in the spinal cord was asymmetrical," and is what would determine the dominant hand. In fact, the favoring of one hand over the other can be seen in ultrasounds in as early as eight weeks. (https://www.businessinsider.com/why-some-people-are-left-handed-2018-1)

Pros

Though they are few, being left-handed does some have some positives! Historical trends have shown that we have advantages in mathematics, sculpting, architecture, painting, music, acting, tennis, commanding, and ruling. We often make better typists, since the most commonly used vowels are on the left side of the keyboard (though when it comes to numerical data entry, we may struggle a bit). There is also some evidence to show that we make better multi-taskers and have higher IQ's!

Cons

Any lefty knows that with the pros come plenty of cons... unfortunately. On average, we are more prone to psychosis and stuttering. This is likely entirely due to outside pressure to suppress left-handedness. We are also more prone to fatal accidents involving machinery and tools designed for right-handed operators. Aside from those more depressing statistics, there are the sillier annoyances, such as desk-chair combos, spiral notebooks, smudging, mugs, ballpoint pens, and the constant question (asked while we are currently writing with our left hand) "are you left-handed?"

Fun Facts

- Only about 11% of the population is left-handed, with women being 3% less likely to be left-handed than men.

- Lefties adjust more quickly to seeing underwater.

- Left-handed people tend to hit puberty later than their right-handed counterparts.

- A high percentage of those with Autism Spectrum Disorder are also left-handed.

- Left-handedness is twice as common in twins.

Famous Lefties

There are tons of famous lefties, including:

Albert Einstein, Buzz Aldrin, Marilyn Monroe, Judy Garland, Michelangelo, Helen Keller, Babe Ruth, Mozart, Jennifer Lawrence, Bill Gates, Julius Caesar, and Kermit the Frog...just to name a few.