In thermodynamics, volume is an extensive quantity whose conjugate tension is pressure. [1] The elementary work exchanged with the surroundings by pressure forces is given by:

dW = -PdV

The translation of the understanding of thermodynamic volume in human reaction systems, e.g. a country, town, or territory, etc., is extremely difficult and is at the core of human thermodynamics. To elaborate, by example, the opening sentence of French chemist Antoine Lavoisier’s famed 1778 The Elements of Chemistry states:

“That every body, whether solid or fluid, is augmented in all its dimensions by any increase of its sensible heat, was long ago fully established as a physical axiom, or universal proposition, by the celebrated Boerhaave.”

In other words, adding heat to a body or system (volume) causes expansion, and this fact is a physical axiom long ago established phenomenon of nature. When translated over into the human sphere, where people are considered as “human particles” or "human molecules", however, the understanding of this expansion boarders on the cutting edge of modern knowledge.

Studies show, for example, that alpha males and alpha females are given more individual or personal space. A supermodel, someone who, according to common oninion, is considered physically "hot", when walking alone through a crowd of people will be given more personal space than as compared to a more homely female. [2] Moreover, when people are asked to approach a stranger and stop when they no longer feel comfortable, they will stop about two feet away from a tall person (22.7 inches to be exact) but less than a foot (9.8 inches) from a short person. As height is correlative with physical attractiveness, e.g. shorter than average men and women are less attractive than taller men and women, it is found, according to attractiveness researcher Nancy Etcoff, that “very attractive people of any size are given bigger personal space and territory; which they carry around with them.” [2] In other words, physically ‘hot’ molecules, in a sense, trigger volume increase be it a gaseous molecule or a human molecule. [3]

Theories
In his 2005 book Entropy and Energy: A Universal Competition, Müller devotes an entire chapter to the subject of socio-thermodynamics. In this chapter, Müller goes through an example of a metaphorical system of hawks and doves competing for the same limited resource. He compares the segregation and mixing of the two populations to that of physico-chemical systems separations defined by phase diagrams. Through his analogies, he correctly correlates pressure-volume boundary work to that of the ‘part of the habitat lost’ and states that ‘such analogies emphasize the point of view that physical or sociological systems of many individual elements have common properties, whether the elements are atoms and molecules or birds and (maybe) men.’ [4]

References
1. Perrot, Pierre. (1998). A to Z of Thermodynamics, Oxford: Oxford University Press.
2. Etcoff, Nancy. (1999). Survival of the Prettiest – the Science of Beauty. New York: Anchor Books.
3. Thims, Libb. (2007). Human Chemistry (Volume One), (preview). (ch. 8: “Planck’s quantum, pgs.213-245). Morrisville, NC: LuLu.
4. Muller, Ingo and Weiss, Wolf. (2005). Entropy and Energy - A Universal Competition, (ch. 20: "Socio-thermodynamics", pgs. 203-21). New York: Springer.