Before the mid-20th century, typologies of love were works of philosophy, ethics, introspection, and intuition. In the 1980s, Robert Sternberg produced a typology of love psychometrically, meaning he asked people about their experiences and used factor analysis to determine which experiences tended to co-occur. He came up with a three-factor model of love: intimacy, passion, and commitment. Intimacy is stuff like warmth, closeness, and bondedness. Passion is stuff like romance, physical attraction, and sex. Commitment is the decisions involved in maintaining love over time. By combining those factors, he came up with the following typology:
| Relationship Type | Intimacy | Passion | Commitment |
| Nonlove | Low | Low | Low |
| Liking | High | Low | Low |
| Infatuation | Low | High | Low |
| Empty Love | Low | Low | High |
| Romantic Love | High | High | Low |
| Companionate Love | High | Low | High |
| Fatuous Love | Low | High | High |
| Consummate Love | High | High | High |
Here’s a typical triangular image of the system:
Nathen's Miraculous Escape 