Chances are your boss takes up a lot of space. Dominant animals show their status with expansive postures, and humans are no exception. Now a study suggests that these poses alter hormone levels. When researchers put subjects' feet up on a table or leaned their bodies forward over a desk, the volunteers experienced a rise in testosterone and a drop in the stress hormone cortisol. “Not only did people feel more powerful,” says lead author Dana R. Carney, a psychologist at Columbia Business School, “but their physiology indicated that they were actually becoming more powerful.” So put your feet up, then ask yourself: Who's the boss?