Why do people fall in love? Why are some forms of love so lasting and others so fleeting? Psychologists and researchers have proposed several different theories of love to explain how love forms and endures.

Love is a basic human emotion, but understanding how and why it happens is not necessarily easy. In fact, for a long time, many people suggested that love was simply something too primal, mysterious, and spiritual for science to ever fully understand.

The following are four of the major theories proposed to explain love and other emotional attachments.

Liking vs. Loving

Psychologist Zick Rubin proposed that romantic love﻿﻿ is made up of three elements:

Attachment

Caring

Intimacy

Rubin believed that sometimes we experience a great amount of appreciation and admiration for others. We enjoy spending time with that person and want to be around him or her, but this doesn't necessarily qualify as love. Instead Rubin referred to this as liking.

Love, on the other hand, is much deeper, more intense, and includes a strong desire for physical intimacy and contact. People who are "in like" enjoy each other's company, while those who are "in love" care as much about the other person's needs as they do their own.

​Attachment is the need to receive care, approval, and physical contact with another person. Caring involves valuing the other person's needs and happiness as much as one's own. Intimacy refers to the sharing of thoughts, desires, and feelings with the other person.

Based on this definition, Rubin devised a questionnaire to assess attitudes about others and found that these scales of liking and loving provided support for his conception of love.

Compassionate vs. Passionate Love

According to psychologist Elaine Hatfield and her colleagues, there are two basic types of love:

Compassionate love

Passionate love

Compassionate love is characterized by mutual respect, attachment, affection, and trust. Compassionate love usually develops out of feelings of mutual understanding and a shared respect for one another.﻿﻿

Passionate love is characterized by intense emotions, sexual attraction, anxiety, and affection. When these intense emotions are reciprocated, people feel elated and fulfilled. Unreciprocated love leads to feelings of despondency and despair. Hatfield suggests that passionate love is transitory, usually lasting between 6 and 30 months.﻿﻿

Hatfield also suggests that passionate love arises when cultural expectations encourage falling in love, when the person meets one's preconceived ideas of ideal love, and when one experiences heightened physiological arousal in the presence of the other person.

Ideally passionate love then leads to compassionate love, which is far more enduring. While most people desire relationships that combine the security and stability of compassionate with intense passionate love, Hatfield believes that this is rare.

The Color Wheel Model of Love

In his 1973 book The Colors of Love, psychologist John Lee compared styles of love to the color wheel. Just as there are three primary colors, Lee suggested that there are three primary styles of love. These three styles of love are:

Eros : The term eros stems from the Greek word meaning "passionate" or "erotic." Lee suggested that this type of love involves both physical and emotional passion.

: The term eros stems from the Greek word meaning "passionate" or "erotic." Lee suggested that this type of love involves both physical and emotional passion. Ludos : Ludos comes from the Greek word meaning "game." This form of love is conceived as playful and fun, but not necessarily serious. Those who exhibit this form of love are not ready for commitment and are wary of too much intimacy.

: Ludos comes from the Greek word meaning "game." This form of love is conceived as playful and fun, but not necessarily serious. Those who exhibit this form of love are not ready for commitment and are wary of too much intimacy. Storge: Storge stems from the Greek term meaning "natural affection." This form of love is often represented by familial love between parents and children, siblings, and extended family members. This type of love can also develop out of friendship where people who share interests and commitments gradually develop affection for one another.

Continuing the color wheel analogy, Lee proposed that just as the primary colors can be combined to create complementary colors, these three primary styles of love could be combined to create nine different secondary love styles. For example, combining Eros and Ludos results in mania or obsessive love.

Lee’s 6 Styles of Loving

There are three primary styles:

Eros : Loving an ideal person

: Loving an ideal person Ludos : Love as a game

: Love as a game Storge: Love as friendship

Three secondary styles:

Mania (Eros + Ludos) : Obsessive love

: Obsessive love Pragma (Ludos + Storge) : Realistic and practical love

: Realistic and practical love Agape (Eros + Storge): Selfless love

Triangular Theory of Love

Psychologist Robert Sternberg proposed a triangular theory suggesting that there are three components of love:

Intimacy

Passion

Commitment

Different combinations of these three components result in different types of love. For example, combining intimacy and commitment results in compassionate love, while combining passion and intimacy leads to romantic love.﻿﻿

According to Sternberg, relationships built on two or more elements are more enduring than those based on a single component. Sternberg uses the term consummate love to describe combining intimacy, passion, and commitment. While this type of love is the strongest and most enduring, Sternberg suggests that this type of love is rare.