Eventually, as humans became more specialized in their speech abilities, a language dominance occurred in the part of the brain that controlled their preferred hand. A theory that was advocated in the nineteenth century was one relating to handedness stemming from a military background. For several millennia, fighting was an important part of life, and most men were given some background in the use of the sword. It is easier to strike an enemies heart by holding the sword in the right hand, since the heart is shifted towards the left side of the body. It was suggested that this stimulated the brain for a predisposition towards right-handedness.
Statistics show, however, that men are three times more likely to be lefty than women.
Not only that, but medical doctors claim that the shift of the heart is of too little consequence to be a factor. Another theory for handedness is related to the last one mentioned. Most soldiers hold their shield with their left hand to protect their heart while engaged in battle, and thus use their right hand to hold their weapon. Those last few theories were ones that are rather obsolete. The next two theories that shall be presented are ones that are currently held as very possible and likely.