Propinquity effect: the more we see and interact with other people, the more likely we are to become our friends. Study of propinquity effect: frie(cid:374)dships a(cid:373)o(cid:374)g mit (cid:373)arried (cid:272)ouples(cid:859) dor(cid:373) (cid:373)ates. Results: % of close friends by neighbor type. More friends from 2nd floor compared to first floor. Mere exposre: the more exposure you get to a neutral object, the more you will like it, does not apply if the object has negative qualities. Confederate sits in front row of class for 0-15 classes. At end of semester, students rate liking of confederate: results. Liking by exposure increased as times confederate sat in class increased. Mere exposure to your own face: we tend to prefer our mirror image over photograph image. Similarity: birds of a feather flock together. Research supports the idea that similarity promotes liking. Study: randomly assigned first year college roommates, measured all sorts of personality traits, attitudes, etc, look at friendship formation after first year.