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Why are some people left-handed? - Daniel M. Abrams-Coolplay.tk 3 years ago
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View full lesson: http://ed.ted.com/lessons/why-are-some-people-left-handed-daniel-m-abrams
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.
Lesson by Daniel M. Abrams, animation by TED-Ed.