Stone age implements which have been discovered seem to be equally divided between left handed and right handed.
When tools became more sophisticated, a clear hand preference emerged (practicality of making two versions of a tool).
Another theory says that as the heart is on the left hand side, a shield would be in his hand to defend it. Any weapon therefore had to be held in the right, which became the dominant hand.
Recent theories have included one that right is the normality and left-handedness, is a deficiency which result from a traumatic birth.
The brain is cross-wired the left hemisphere controls the right handed side of the body and vice-versa:
The left hemisphere (RIGHT HAND CONTROL) controls the following Speech, Language, Writing, Logic, Mathematics, Science, this is the LINEAR THINKING MODE.
The right hemisphere (LEFT HAND CONTROL) controls the following Music, Art, Creativity, Perception, Emotions, Genius, this is the HOLISTIC THINKING MODE.
Whether there is a genetic reason for handedness is a contentious subject. It certainly seems to be true that left-handedness runs in families, although not in any predictable way. Various researchers have looked at groups of families and tried to work out the probabilities of left and right-handed parent combinations having left-handed children, but they all come up with different figures.
