Amy Cuddy made the power pose famous. The social psychologist, former Harvard Business School professor, and author has become a popular--and controversial--figure for her advocacy of using certain physical postures to build confidence and perform better under stress. Her 2012 TED Talk on the subject has been viewed more than 54 million times. At the 2019 Inc. 5000 Conference in Phoenix on Friday, Cuddy described the research behind her theories and how they can be useful for leaders.

"Personal" power, Cuddy argued, is just as important for leaders as competence is, and is unconnected to "social" power, or power over others. It's "the ability to control our own states and behaviors, and it's infinite--it's not zero-sum," she said. Personal power allows you to approach challenges with optimism, to see other people as allies rather than as threats, and to be more generous. "When you feel personally powerful, you are more likely to be able to empower the people who work for you," she said. 

If you're already doubting yourself, it won't help to simply tell yourself that you're powerful, Cuddy contended. However, she argued that you can trigger the feeling through physical actions. Breathing deeply will help you feel more relaxed, of course, while speaking more slowly--"taking up space temporally"--is an expression of confidence. And practicing "expansive" poses in private before a job interview or an investor meeting can reduce stress and ultimately have a profound effect on how other people perceive you, she said.

The effectiveness of physical expressions of power is evidenced by the fact that they're universal across cultures, Cuddy said, citing sports as an example. Olympic athletes from around the world tend to demonstrate the same victory pose: arms raised, chin up, mouth open. The opposite postures--slouching, making yourself smaller, and covering your face--signify powerlessness and shame.

Cuddy also noted that gender stereotypes about body language, which children begin to absorb at a very young age, affect women's ability to claim the same level of power as men. "We need to allow our daughters to expand, to take up some space, to express their ideas, and to show their strength, because this benefits all of us," she said.