Why most people are right handed.
This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights . Roughly 90 percent of humans are right-handed and this is one of the traits that separates us from most other primates who don't really show any overall preference for left or right handedness. It's believed that handedness played an important role in human evolution, with a recent study on the earliest evidence of right-handedness in the fossil record shedding light on when and why this trait arose. Interestingly, the clues were found not in our ancient hands, but in our ancient teeth. We have long known that the human brain is composed of two roughly similar halves. The left hemisphere controls language and motor abilities, whereas the right hemisphere is responsible for visual-spatial attention. It is less well known that brain lateralization, or the dominance of some cognitive processes in one side of the b