Eli5:what’s the cause of someone being right or left handed? And why the vast majority is right handed?
In: Biology
Lots of ideas, not a lot proven yet. The lobes of the brain and their control over different aspects seem to be most likely. We see effects from this in many ways.
One interesting reason proposed is that we tend to carry babies on our left side. Which leaves our eventually dominant hand free for tasks. There are various things associated with holding babies on the left such as the baby hearing a heartbeat, or it being a less sensitive breast, or even that communicating and connecting is better that way because of brain arrangement. But it’s also possible that we carry babies on our left because we tend to be righthanded since people tend to carry babies in their less dominant arm.
Fun fact, you have a dominant leg (makes the first step, differences in balancing and pushing off), dominant eye (preferred for looking through microscope), even a dominant ear (one ear is usually the one that gets an earbud left in when trying to hear what someone says to you). These can be the same as your handedness but can also vary. Most righthanded people tend to overall have a right-side dominant, but lefthanded people usually vary more. Here’s a fun little way to test [https://www.scientificamerican.com/article/bring-science-home-dominant-side/](https://www.scientificamerican.com/article/bring-science-home-dominant-side/)
Personally, I’m a bit skeptical that we tend to be righthanded because we carry babies with our left. Because animals usually also have dominant sides. They seem to tend to be more evenly split than humans though. Although female cats tend to be more often right-pawed.
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