
Today, about one-tenth of the world’s population are southpaws. Why are such a small proportion of people left-handed -- and why does the trait exist in the first place? Daniel M. Abrams investigates how the uneven ratio of lefties and righties gives insight into a balance between competitive and cooperative pressures on human evolution. 

Why Are Some People Left Handed

why-are-some-people-left-handed

Let's do English ESL deep listening: focus on meaning. 
Today, about one-tenth of the world’s population are southpaws. Why are such a small proportion of peopl…