Handedness represents a personal preference towards one hand or the other, in terms of speed, accuracy, and precision. This preference is extremely uncommon in the animal world but is very common for humans and chimps where the preference for right hand dominates. The thing is, we still don’t know what effects this preference has, or why people are right or left handed in the first place, though several studies have been conducted on this topic.
Here are just some of the facts about left-handed people we’ve learned through science:
- Twins are more likely to be left-handed and we have no idea why. A 1996 study assessed the handedness of 1616 twins (808 twin pairs) aged 6 to 28. The study found that more twins were left-handed than the global average but didn’t draw any conclusions on why this happens.
- Lefties earn significantly less money than right-handed people. A Harvard University team found that lefties earn between 10% and 12% less every year than righties do. They attributed this difference to “observed differences in cognitive skills and emotional behavioral problems.”
- If both parents of a child are left-handed, there is a 26% chance the child will be left-handed as well.
- Left-handed people don’t actually have a lower life expectancy. This is probably the biggest myth associated with handedness, arguably originating from a rather poorly done study in the late 1980s by Halpern and Coren. This myth was perpetuated without criticism for decades by the media and embedded itself into popular culture. There are several reasons why this bias emerged, but the biggest one is probably the fact that for a long time, left-handedness was shunned and people were forced to use their right hand. As a result, many left-handed people would not declare themselves as such, significantly skewing the data.
- Right-handed people have higher cognitive skills, less behavioral and speech problems, less often have learning disabilities, and more often graduate their school (on average), but lefties produce an above-average quota of high achievers.
- Rough births: left-handed people are statistically more likely to suffer from birth-weight and complications at birth.
- Handedness may develop in the womb. Scientists from Queen’s University, Belfast in the UK reached this conclusion after using ultrasound scans to see how fetuses suck their thumbs. Ten years later, 100% of the fetuses who sucked their right thumb were right-handed, while 67% of those who sucked their left thumbs were left-handed (arguably switching due to societal pressures).
- Lefties remember events better than facts. Dr Stephen Christman and Dr Ruth Propper, of the University of Toledo in Ohio concluded that the two halves of the brain work together in episodic memory to help remember events for lefties.
- Lefties are better at video games. According to research conducted by Dr. Nick Cherbuin at the Australian National University, left-handers often outperform their right-handed counterparts at fast or difficult tasks involving a large amount of information or stimuli. These tasks include activities such as talking while driving, piloting jet fighters, and playing fast-paced video games.
- Left-handers thrive because they’re better fighters, a study published in Proceedings of the Royal Society B claims. It is also believed that lefties do better at some sports, but this is still a topic of hot debate.
- Left-handed people are often excluded from studies. Lefties really do have different brains and genes from right-handed people, yet left-handed people are almost never included as study subjects in scientific research. We understand so little about this difference and what it means, and yet many scientists refuse to include lefties in specific studies.
Copyright 2016 ZME Science
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