2015-02-03

[public] 10.0M views, 197K likes, dislikes audio only

TED-Ed

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.