Her theory: Stand like Wonder Woman for two minutes before a big meeting or event, and your confidence will spike — as if by magic.
Four years later, the Harvard psychologist has released an entire book on the virtues of changing your posture to change your attitudes.
It's called "Presence: Bringing Your Boldest Self to Your Biggest Challenges," and power posing isn't the only piece of advice anymore.
Here's something else to try.
"Before heading into a situation where we may be challenged," Cuddy writes, "we can reduce our anxiety by reaffirming the parts of our authentic best selves we value most."
By that she means literally telling yourself, either out loud or by writing it down, what you like and treasure about who you are. These are called "self-affirmations."
The affirmations don't even need to relate to the challenging situation. You could be minutes away from interviewing for your dream job, and reminding yourself that you are funny or good at tennis should help quell your nerves.
This seems counter-intuitive, but there is some research backing it up.
In one 2005 study Cuddy references to in "Presence," two psychologists asked a group of people to give an impromptu speech to a team of judges. After the speech, they were told to count backward from 2,083 in intervals of 13. This went on for five minutes, all the while the judges would yell "Go faster!"
One group of participants was instructed to write self-affirmations before these tasks, while another just went in cold.
In follow-up tests, Cuddy says, the subjects' levels of cortisol (a hormone released when we're stressed) did not spike if they'd written self-affirmations beforehand. "In fact, the self-affirmation group experienced no increase in cortisol at all."
According to Cuddy, hundreds more studies like this all back up self-affirmation as the ticket to reducing anxiety. The reasoning is rather straightforward.
When we enter challenging events, ones where we know we'll be judged by others, stress can fill us with doubt. We may easily lose sight of our strengths, and instead focus exclusively on our nerves and potential shortcomings.
Self-affirmations remind us that even if we don't get the desired outcome, we won't be spineless piles of goop once it's all over.
We'll still be funny and good tennis players, and it's that reassurance — that we aren't as fragile as we might think — that can give us confidence like we've never seen before.