What pattern of organization is propinquity effect and why?

The propinquity effect is the tendency for people to form friendships or romantic relationships with those whom they encounter often, forming a bond between subject and friend. Occupational propinquity, based on a person's career, is also commonly seen as a factor in marriage selection. Workplace interactions are frequent and this frequent interaction is often a key indicator as to why close relationships can readily form in this type of environment.