One of the concepts of chaos mathematics and complex system is phase transition or tipping point (AKA bifurcation). This concept argues and proves that when a certain ratio (0.5) between elements in a system and their interaction reached, the system will experience a significant change. A known simulation of this concept is the button and thread where randomly buttons are connected with threads, and the size of the clusters measured.
The same concept applies to people in organizations. When a specific ratio between the number of people in the organization and their random interaction reached, there will be a significant change in the system. That is the reason why companies are spending time and effort to create common areas in the office to increase the random interaction between people. The business literature, by the way, has a lot of great examples of how random interaction helped business.
On top of designing your office to maximize interaction between human beings you can design your organization’s teams to increase random interactions. The best way to do it is to shy away from department and silos and implement a strategy of hybrid groups that created from all expertise (from traditional silos) needed to reach a business function purpose. Hybrid groups required people to interact with many other people, especially in ad-hoc groups (mainly projects).