<P> In social psychology, propinquity (/ prəˈpɪŋkwɪtiː /; from Latin propinquitas, "nearness") is one of the main factors leading to interpersonal attraction . </P> <P> It refers to the physical or psychological proximity between people . Propinquity can mean physical proximity, a kinship between people, or a similarity in nature between things ("like - attracts - like"). Two people living on the same floor of a building, for example, have a higher propinquity than those living on different floors, just as two people with similar political beliefs possess a higher propinquity than those whose beliefs strongly differ . Propinquity is also one of the factors, set out by Jeremy Bentham, used to measure the amount of (utilitarian) pleasure in a method known as felicific calculus . </P> <P> 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 . 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 . In other words, relationships tend to form between those who have a high propinquity . It was first theorized by psychologists Leon Festinger, Stanley Schachter, and Kurt Back in what came to be called the Westgate studies conducted at MIT (1950). The typical Euler diagram used to represent the propinquity effect is shown below where U = universe, A = set A, B = set B, and S = similarity: </P>

The theory of selecting a mate based on nearness is called