Almost all people in this world, more often use the right hand for everyday activities ranging from eating, writing, holding something, and others. Less than 10 percent are used to left-handed or more actively using the left hand.
Apparently, it is a feature that makes humans different from the primate animals that are active with both their hands. Right-hand preference is more active from the left it is believed to have existed since early humans.
Scientists who try to solve the reasons what trigger human more active with their right hand, suspect the cause is the ancient tools used by these early humans. Well, this is just a guess because scientists certainly cannot explain it.
The left brain and right brain of humans have different control functions. If the left more play a role in the control of language and motor done by humans, then the right brain more to the visual attention or space and place (spatial).
Experimental research scientists who want to make an ancient equipment like the ancient people, requires them to work more on the right hand. In situations and conditions similar to the limitations of ancient times, scientists see that the left brain is more work and active than the right brain.
The ancient equipment is found in Kenya, Africa, and is estimated to be more than 3.3 million years ago. The evolution that occurred in a long time is believed to trigger the habit of ancient people to more actively using the left brain eventually decline until modern humans today.
The left brain that controls the right body makes the human right hand more active than the left hand. While the right brain that controls the left side of the body is more passive in daily activities.
Scientists also mention that one cause of lefties is genetic, or derived from the family.