Every interaction is a value proposition.

Think about being at a party that you hosted and 15 people are talking to you. You intrinsically will only hear those with the highest value proposition, a cute girl, an investor you invited, your friend. You might not be making a concious effort but your brain is.

Now if most interactions are value propositions from one party to another then it makes sense that your personal behavior will reflect your own power dynamics in order to increase your own value proposition to the other party. This includes things such as body language.

For years and years no one cared about this stuff, now its all coming out of the woodwork as a terrible thing to practice when its been practiced for years and written about by Machiavelli and Robert Greene.