correlation between affiliation and similarity of intelligence, attitude, education, age, religion, SES, etc.
need complementary - people choose relationships so they mutually satisfy each others needs
potency of physical attractiveness - attractiveness stereotype says we attribute positive qualities and desirable characteristics to attractive people
spatial proximity - tend to develop a greater liking to someone who lives closer because they are more accessible and there is an increased intensity of initial reaction
mere exposure hypothesis (Zojanc) - based on familiarity, repeated exposure leads to increased liking