Comment by skyberrys
9 hours ago
The article didn't really help me understand what it was about bipedalism that resulted in a right handed preference. Also in my family left hand dominates, we are a cluster of left handed people. My theory is if any child wants help with fine motor control the help is provided by a left hand to a left hand.
The original paper is titled "Bipedalism and brain expansion explain human handedness". It doesn't seek to explain why we have a right-handed preference specifically (vs left-handed), but rather why humans have such a strong handedness preference compared to ancestors who had only a mild right-handed preference.
IOW, why handed vs ambidextrous, not so much why left-handed vs right-handed.
> why handed vs ambidextrous
Did it even explain that? I'm ambidextrous, I have no handedness bias, so whichever I pick up to first learn something is the hand I use. So I'm a mix of left-handed and right-handed depending on the task. And yet I didn't really understand why that's odd because of my bipedalism?
There is also a category of people who are “mixed-handed”, who have a strong handedness preference for a given task, but which hand one prefers varies based on the task. I didn’t know about this category until recently, but it describes my personal experience.
Mildly informative Wikipedia article: https://en.wikipedia.org/wiki/Cross-dominance
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>why handed vs ambidextrous
may be high dexterity is expensive, brain-wise, i.e. may be the choice given average brain is either 2 hands with mild dexterity or a one of high dexterity at the expense of the other. With tools, etc. the latter choice seem to be preferable and was selected for (and the lucky ones get to have 2 of high dexterity) Bipedalism and brain expansion in this situation are indirectly connected to the handedness as they are enablers and drivers of tools use.
> My theory is if any child wants help with fine motor control the help is provided by a left hand to a left hand.
Neither of my parents were left handed, and yet, here I am; despite attempts otherwise I might add.
Oddly enough, a lot of my "nerd friends" are left handed, and I'm also left handed. /shrug
Funny enough, this made me realize that although I'm right-handed, I'm left-footed when it comes to football. As an amateur player, using my right foot with proper shooting form still feels surprisingly awkward to me.
All our maths teachers were at school were left handed, along with 25% of the top maths set in our year. The teacher and student population of left handed people were close to the normal 10% levels too.
Autistic people are 2 to 3 times more likely to be left handed than the general population.
without reading .. my immediate guess is that one hand is needed for maintaining upright balance, while the other hand grasps something important ?
As someone who is fairly ambidextrous, but predominately a lefty - the things that are harder to switch between are some of the gross motor skills.
For example, throwing (or kicking) with your non-preferred side is not as simple as picking up and throwing a ball or simply kicking it. You have to adjust your position and stride to lead with the correct foot. I found learning right-handed pace bowling in cricket (for fun) especially challenging as you have to land your back foot in the right place as you bowl through the popping crease. A few steps and rolling the arm over to spin was easy, and I actually can get more spin on the ball with my right hand.
My theory is that the handedness came about through learning basic survival activities such as running and jumping, throwing spears or rocks, etc that require using a preferred or learned hand.
This is true for me as well. I can't really play volleyball, because you are supposed to hit the ball with both hands, but my left hand is constantly ahead of my right hand. All my shots are crooked.