Peper wanted to find out why. In 2012, he studied it with 110 students and co-authored a journal article in Biofeedback concluding that postures like skipping gives students more energy, and a slouched position gives them less.

Other studies also show how posture and movements can affect our minds. Elizabeth Broadbent, an associate professor of health psychology at the University of Auckland, went out for a walk one day feeling sad, but then she noticed that as soon as she lifted her head and started looking straight ahead, she felt much better. Her article in the journal Health Psychology concluded that upright posture is linked to higher self-esteem and less fear, whereas a slumped posture is linked to people feeling worse about themselves.

Broadbent has done a follow-up study looking at how posture impacts people with mild depression and whether or not it could be part of therapy.

Dance movement therapist and researcher Tal Shafir at the University of Haifa noticed that dancing made her feel better. Her article, which was published in Frontiers in Psychology this January, linked the basic emotions anger, fear, happiness and sadness to specific movement characteristics.

Shafir tells the story of a fellow dance movement therapist working with a person with an injured shoulder who was getting physiotherapy. Once the patient recovered enough to raise her arm up, she started laughing, saying: “You know I haven’t laughed in a long time, and suddenly I feel the need to laugh.” Shafir says this shows that sometimes a certain posture or a certain movement can affect how we feel.

This idea of a mind-body connection was not considered in mainstream medicine in the past, but now researchers are studying it in earnest, looking at how it can be used in therapy.

“I think it’s kind of like yoga and mindfulness and meditation, which until recent years, people didn’t believe in it and didn’t take seriously,” Shafir says. “They considered it alternative therapy. This is not alternative therapy; this should be considered regular therapy.”

Amy Cuddy, associate professor of business administration at Harvard Business School, says she is excited by this research. In 2012, she spread the concept of “power posing” with a TED talk that has been watched more than 30 million times. The idea is that doing an expansive pose (think Wonder Woman in a star-shaped pose with her hands on her hips) for about two minutes before a stressful task gives us confidence by boosting testosterone, a hormone linked to risk-taking and lowering levels of the stress hormone cortisol) and can help us succeed.

Cuddy also says that these body-based therapies are being studied more in mainstream clinical psychology. She points to the work of Emma Seppälä, science director of Stanford University’s Centre for Compassion and Altruism Research and Education, who showed in two published studies that breathing exercises and meditation helped US veterans of the wars in Iraq and Afghanistan recover from post-traumatic stress disorder.

“I’m really encouraged by that,” Cuddy says. “I would love to see clinical interventions that are body-based. I’d like to make this accessible to people and not have them feel like that’s only for people who go to yoga retreats. I would like people to see this as actually very straightforward and simple.”

One task that makes many people nervous is public speaking, and Brian Hodgson, a public speaking coach in Hong Kong, says he has seen many examples of how body language can be critical to the success of a speech. He cites the example of a recent client who works at a bank.

“People always seemed to be a bit more negative towards him. He was quite a nervous person, quite shy, and the reason why people were against him was because when he spoke, he actually spoke with his hands on his hips, which is an aggressive position to take,” Hodgson says. “Although he himself was not so confident, he demonstrated by his body that he was seemingly aggressive, and the audience would then react by not taking his message so easily.”

Hodgson suggested the client talk with his hands on his sides and use open-handed gestures. It did the trick.

In another article by Cuddy published in Psychological Science, she shows that adopting expansive poses (even subconsciously by sitting in a bigger chair) also gives people power, and makes them more likely to be dishonest like steal money, cheat on a test, and park illegally.

“I think we have a clear pattern that expansive postures, or postures from the environment, can make you feel more powerful and it leads to corrupt behaviour,” says Cuddy’s research collaborator Andy Yap, assistant professor at INSEAD in Singapore, who studies the psychology of power.

But Yap adds that power is more complicated than just posture; for example, it’s hard to predict how the expansive chairs would interact with other factors like hierarchy or titles.

“If you are a very low-ranked secretary and you have a very expansive desk, will you feel more powerful? We don’t know. If you are a CEO and you have a very tiny desk … will you feel less powerful? We don’t know,” he says.

Yap advises against drawing serious conclusions from these power principles without more research. Richard Petty, chair of the psychology department at Ohio State University, says the research is promising, but agrees with Yap.

“I don’t think there’s any harm in it, but in terms of having confidence that it will work when you are doing it deliberatively, I don’t think the evidence is quite there yet,” says Petty.

Petty has studied “meta cognition” – what we think about our thoughts. He showed in three studies that we can make ourselves more confident in what we think by nodding, writing down those thoughts and keeping them close (like in a pocket), and sitting up straight; we make ourselves less confident by shaking our heads, slumping, and throwing away the bit of paper with our thoughts.

All the researchers agree that we’re a long way from understanding exactly how the poses and movements affect our nervous systems. Cuddy says that makes this an exciting time.

“We’re just starting to figure out how to measure these things, and part of it is because the body-mind work was kind of marginalised in the past and not seen as mainstream,” she says. “We’ve only touched the very tip of the iceberg.”