A Harvard psychologist says these simple body-language tweaks can instantly boost your confidence

In 2012, Harvard Business School professor Amy Cuddy gave a now-famous TED Talk on the benefits of "power posing," or changing your body language in ways that can make you feel more confident.

In her new book "Presence," Cuddy further explores the benefits of mimicking the body language of powerful people. She argues that power posing can be more effective than traditional confidence-boosting exercises, like telling yourself how great you are.

She describes power poses as expansive and open. When you adopt one, you take up a lot of space and hold your arms and legs away from your body.

For example, in "The Wonder Woman" power pose, you stand with your feet apart, your hands on your hips, and your chin tilted upward.

Cuddy suggests that our attitudes often follow from our behaviors, as opposed to the other way around. That means assuming the body language of a powerful person can make you feel confident. On the other hand, shouting, "I'm awesome!" requires first a substantial attitude shift, which most of us know isn't so easy to make.

In the book, Cuddy puts power posing in the broader context of what she calls "self-nudges," or small tweaks to your body language and mindset that can produce psychological and behavioral improvements in the moment. She borrows the term "nudge" from economists and psychologists who discovered about a decade ago that you can spark significant behavior changes by nudging people in the right direction.

Power posing is an example of what Cuddy calls a "body-mind nudge." Body-mind nudges, she argues, allow you to skip over psychological stumbling blocks like trying to believe that you're awesome, confident, and perfect, when you clearly don't believe that at all - at least not right now.

Cuddy writes: "Body-mind approaches such as power posing rely on the body, which has a more primitive and direct link to the mind, to tell you you're confident."

What's more, Cuddy says, adopting the body language of a powerful person changes the way other people see and act toward you, which in turn reinforces your confident behavior.

"When our body language is confident and open," she writes, "other people respond in kind, unconsciously reinforcing not only their perception of us but also our perception of ourselves."

So how can you use this strategy the next time you're faced with a challenging situation?

Check out some of the power poses that can boost your confidence at work: