Theories in Social Psychology and Evolutionary Psychology in relationships

links: Love and Sex Psychology

Social Psychology

Interdependence Theory describes how partners perceived value of each other, and how they coordinate behaviours based on different situations.

Evolutionary Psychology

Darwinian Evolutionary Theory explains the selection of survival, meaning that species will filter certain traits or genes via reproductive selection.
Handicap Principle explains why some species have developed sexual characteristics that are harmful to survival.
Parental Investment Theory