Having the opposite handedness of most other people (i.e. being left-handed) is an advantage in a fight. That's because righties are used to fight against other righties because most people are righties, lefties are also used to fight against other righties. It means that when a lefty fights a righty, the lefty is in a familiar situation while the righty is not, giving the lefty an advantage. And indeed, in many sports where you have an opponent, at high level, there is a higher than normal proportion of lefties.
On the other hand (pun not intended), having the same handedness as most other people (i.e. being right-handed) is an avantage for cooperation. For example, to righties can easily share a tool made for righties, but it will be awkward for a lefty.
So there are two opposing forces here: cooperation tends to make people of all the same handedness, while competition pushes for a 50/50 distribution. We are at about 90/10, suggesting that the cooperation aspect is more important but not absolutely so.
That dominant side is the right side is probably just due to random chance. That it doesn't differ between population groups suggest that it happened before humans spread around the globe, possibly before humans were human.
Having the opposite handedness of most other people (i.e. being left-handed) is an advantage in a fight. That's because righties are used to fight against other righties because most people are righties, lefties are also used to fight against other righties. It means that when a lefty fights a righty, the lefty is in a familiar situation while the righty is not, giving the lefty an advantage. And indeed, in many sports where you have an opponent, at high level, there is a higher than normal proportion of lefties.
On the other hand (pun not intended), having the same handedness as most other people (i.e. being right-handed) is an avantage for cooperation. For example, to righties can easily share a tool made for righties, but it will be awkward for a lefty.
So there are two opposing forces here: cooperation tends to make people of all the same handedness, while competition pushes for a 50/50 distribution. We are at about 90/10, suggesting that the cooperation aspect is more important but not absolutely so.
That dominant side is the right side is probably just due to random chance. That it doesn't differ between population groups suggest that it happened before humans spread around the globe, possibly before humans were human.