Live Science | Life's Extremes: Left- vs. Right-Handed
Per livescience.com, to get a sense of human handedness, take a survey of those combination chair-desk furniture pieces in classrooms. The desktops tend to wrap around from the right. That's so right-handers can comfortably rest their arms while jotting down notes with their dominant hand. For that uncommon left-hander, if he or she is lucky, there might be an odd-looking desk or two with an oppositely molded desktop.
Such classroom chauvinism reflects the puzzling strong bias toward right-hand dominance in our species. All over the planet, nine out of 10 people, on average, favor their right hand for writing, throwing and so on. ("Footedness" roughly follows this same breakdown, though for sensory organs, such as eyes and ears, preference is less skewed; true ambidexterity occurs in less than 1 percent of the population.)
Scientists still aren't sure what causes handedness and why nine out of 10 people are right-handed, with just a small percentage being left-handed, though they suspect genetics is involved. True ambidexterity occurs in less than 1 percent of the populatio