Group Theory

Or how teams get exponentially dumber as the number of members increase...

One commonly held inflection point is ~150 (I'm using the layman's definition of the phrase, not the mathematical one)
Wikipedia article on Dunbar's number

In his 2000 best-seller The Tipping Point, author Malcolm Gladwell described Gore’s traditional practice of limiting the size of its plants to roughly 150 workers, because that was the largest group of people who could know one another well enough to converse in the hallway.

Link to Workforce Management article about W.L. Gore

Another classic example of a "tribal" workplace is GE's Durham jet engine plant

Link to FastCompany article

GE/Durham has more than 170 employees but just one boss: the plant manager. Everyone in the place reports to her. Which means that on a day-to-day basis, the people who work here have no boss. They essentially run themselves.

The jet engines are produced by nine teams of people -- teams that are given just one basic directive: the day that their next engine must be loaded onto a truck. All other decisions -- who does what work; how to balance training, vacations, overtime against work flow; how to make the manufacturing process more efficient; how to handle teammates who slack off -- all of that stays within the team.

Everyone knows how much money everyone else makes, because employees are paid according to his or her skill. There are three grades of jet-assembly technician at this plant -- tech-1, tech-2, and tech-3 -- and there is one wage rate for each grade. There is no conventional assembly line. One team "owns" an engine from beginning to end -- from the point when parts are uncrated and staged to the moment a team member climbs on a forklift to place the finished engine on a truck for shipment. The members of the team do the jobs that interest them. No one ever does the same job, shift after shift, day after day. There is usually choice -- and there is always variety.

This plant has no time clock. Workers leave to go to their kids' band concerts and Little League games. Every technician has an email address and Internet access, voice mail, business cards, and a desk shared with one teammate. The plant manager -- the boss -- sits in an open cubicle that's located right on the factory floor: Engines float by, just 20 feet away.

...

The techs at GE/Durham have challenging jobs that matter, they have a degree of control over their work that is almost unprecedented, they adhere to demanding performance standards, they receive the training and support that they need to do the best work they can--and, as a result, they do just that. There is somethng so extraordinary about this place that you wish you could walk through it with Karl Marx and Max Weber--just to hear them explain how its revolutionary culture squares with their theories about the dehumanization of work in modern society.