Just as peacocks fan their tails to attract a mate and chimpanzees bulge their chests to assert their hierarchical rank, humans make power-poses to show their power and command respect. These are the results of a study by Amy C.J. Cuddy, a social psychologist at the Harvard Business School.
The study, published in the journal Psychological Science, randomly selected 42 participants--26 of them women--and assigned them to assume and hold a pair of either low- or high-power poses. The high-power posers spent one minute sitting in a chair in front of a desk, with feet resting on it and hands clasped behind the head, and, in the other pose, they stood, leaning forward over a table, with arms out and hands resting on the table. In both poses, the participants took up space, an expression of power not unique to the human world.
This goes a long way to explain why Yoga makes people feel powerful, as well as the evolutionary basis for self confidence: "These power poses are deeply intertwined with the evolutionary selection of what is ‘alpha,'" Cuddy wrote.