For example, make yourself small. Look down at the floor. Maybe put your hand on your neck and cross your legs. Just two minutes of holding this kind of pose has been found to lower testosterone and increase cortisol, making you feel less confident than you did before you started posing.
Conversely, try to take up as much space as possible.
Sit like you own the place. Stand like you're a rock star. Your body will start sending signals in the opposite direction, making you feel more powerful than before you began posing.
Effective leaders are found to have consistent and specific patterns of testosterone and cortisol in their body, resulting in dominant and non-stress reactive behavior. These are leaders who are assertive yet laid back.
The most interesting part of these experiments is that Amy Cuddy did not identify powerful and powerless candidates through any sort of screening process, or through in-depth psychological tests. She simply posed people in either a high power pose or lower power pose, selecting at random, before putting them in a stressful experimental situation. Two minutes in one of the high power poses is all it takes for a person's testosterone to increase and cortisol to drop, both at statistically significant levels. The low power pose had a similarly significant effect in the opposite direction.
In other words, the difference between feeling powerful or powerless could be as simple as changing how you stand or sit.
Amy Cuddy delivers a great twenty-minute talk about her research here.
To me, this suggests a reason why yoga is so popular. Yoga is essentially a 60 to 90 minute flow from one high power pose to another.
(If you don't think yoga is a good workout, find a more intense yoga studio). My understanding of the origins of yoga is fuzzy at best, but it seems agreed that yoga was originally developed thousands of years ago as a tool to help meditation, not as a form of exercise. Meditation was the main task, and yoga was simply a tool to help train the mind.
It makes complete sense to me that yoga can actually change how you feel and how your mind works. That's what it was made for, and Amy Cuddy's research provides a nice piece of science to support the continued practice of an ancient art.