There is a 90% you are right handed, 9% chance you are left handed and 1% chance you are ambidextrous. Why?
Hand dominance isn’t normal for primates; in fact humans are the only primates that have it at all. Other animals like cats and dogs do favour the left or right paw but it’s about a 50/50 split. What’s happening here?
Some scientists say that somewhere in our genome there must be a left or right hand gene as handedness usually runs in a family but there have been cases of identical twins with identical genes not having the same dominate hand. If there is a handedness gene it has yet to be found.
A study in 2012 had a different view on handedness. The theory being that humans determined handedness early on for cooperation. If all the tools of the tribe are for the right hand it makes cooperation WAY easier. Again however we lack proof to corroborate the theory.
Finally the most widely accepted theory. The asymmetry of our brains. Our brains are contralateral which means that the left hemisphere controls the right side of the body and vice versa. The sides of the brain also determine certain processes of thought as seen below.
The theory states that people who use primarily the right hand are left brained people. The left side of the brain processes language so it only make sense that the right hand would more commonly be used to write language down. To add to that some lefties tested process language evenly across the brain and in some cases entirely on the right side. It could be that natural selection just whittled down the gene pool to primarily produce right handed people as it would be easier to function in a right handed world.
Finally there are the 1% like myself who are ambidextrous. Basically no research has been done as to why we happen. I guess we’re aliens!
What hand do you use? Which theory sounds best to you? Let me know in the comments!
Don’t forget if you have any science questions to ask away!