"simply holding one's body in expansive, "high-power" poses for as little as two minutes stimulates higher levels of testosterone and lower levels of cortisol" -- Power Posing: Fake It Until You Make It
That's what I call a paleo hack!
Good topic. This study relates to the field of embodied cognition, whereby researchers have found links between physical state of the body and mental attitudes. Recent studies have found that:
Handing someone something that's warm (e.g. coffee) causes them to think of you as having a "warm" personality.
Holding something heavy while making a decision causes you believe that the decision you're making is "weighty."
Forcing someone to smile by having them hold a pencil in their mouth improves their mood.
Crossing your arms makes you more resistant to outside influence.
Physically stepping backwards a step seems to help you reevaluate things ("take a step back") mentally.
Feeling guilt can cause you to want to wash your hands.
IMO, those high power poses are also welcoming challengers so be prepared for that. I worked in finance the last 6 years and my old associate used to do this. I really really felt an urge to fight him every time he did it. When a peer tries to "alpha male" around another male they should be prepared for the other male to react back.
My own experience bears this out. If I arrange my face into a little smile, like the "archaic smile" found in ancient Greek sculptures, I feel my mood lift in just a few minutes. Ditto with posture...when I hold myself errect and proud, I soon start to feel more confident and self assured.
This is why yoga can have such dramatic effects on the body, way beyond it's value as mere exercise. I've known a few yoga teachers (all Ashtanga practitioners) who ended up with v high testosterone levels and almost excessive sex drives. Some yoga postures seem to be particularly powerful for dealing with depression and anxiety.
The psy.plymouth.ac.uk/research/ece/publications link given above is dead. For some reason, a search of it at that site redirects to Cambridge University Embodied Cognition & Emotion Laboratory here: http://www.psychol.cam.ac.uk/cece/research