In 2010, researchers Amy Cuddy, Dana Carney and Andy Yap reported that people who adopted expansive postures — so-called “power poses,” like putting your hands on your hips — had higher levels of the “macho” hormone testosterone and lower levels of the stress hormone cortisol, and were more likely to take risks than those who struck more timid poses, such as crossing your arms. People soon started assuming Superman-like stances to step up their game in high…