In psychology, experts often separate love into two main types: passionate love and companionate love. Evolutionary theories say these two types of love serve different purposes, and studies in psychology and biology show they work in different ways. Both types can help make relationships satisfying. Passionate and companionate love are different from a third type called compassionate love, which is about caring for others.

Passionate love is sometimes called "romantic love" in some areas, like biology, but psychologists usually use "passionate love" instead. There is no single term used by all experts to describe love. Other terms similar to passionate love include "being in love," having a crush, obsessive love, limerence, and eros.

Companionate love is often called "attachment" or compared to strong liking, friendship love, or storge. This is usually seen as the same as the "attachment system" in attachment theory, though not all experts agree.

Passionate love

Passionate love feelings are often measured by psychologists using a questionnaire called the Passionate Love Scale (PLS). In the PLS, Elaine Hatfield and Susan Sprecher describe passionate love as involving intense emotions such as joy, fulfillment, anguish, and agony. Hatfield explains that the word "passion" originally meant "agony," as in the suffering of Christ. Passionate love is not an emotion itself but a motivational state that leads to different emotions depending on the situation, such as happiness when love is returned or sadness when it is not. A 2014 study of Iranian young adults found that the early stage of romantic love was linked to feelings of happiness, increased mental and physical energy, and better sleep, but also to stronger symptoms of depression and anxiety. The researchers concluded that romantic love is not always a happy time in life.

Passionate love is usually strongest in the early stages of a relationship, when it is new or before it begins. However, in rare cases called long-term intense romantic love, strong attraction can last for many years, even 10 years or more.

In modern studies, passionate love is sometimes seen as a mix of different feelings. For example, the PLS includes questions that measure companionate love, which led Sandra Langeslag and others to create the Infatuation and Attachment Scales (IAS) as a newer way to measure passionate and companionate love. The PLS also includes an obsessional element, which is different from intense attraction because it is possible to feel love with less obsession. While Hatfield originally described passionate love as including sexual attraction, modern authors agree that sexual and romantic attraction are different. People are motivated to form and keep a relationship in a way that is separate from sexual desire, and it is possible to fall in love without sexual feelings.

Langeslag and others developed the Infatuation Scale, which includes questions such as:
• Thinking about the person a lot, even when not together.
• Feeling nervous or shaky when near the person.
• Losing interest in food because of thinking about the person.
• Having trouble focusing because of thoughts about the person.
• Worrying about saying the wrong thing when talking to the person.
• Feeling sweaty or nervous when near the person.
• Becoming tense when close to the person.
• Having trouble sleeping because of thinking about the person.
• Looking for hidden meanings in the person's words.
• Feeling shy when with the person.

Langeslag and others found that infatuation is more linked to negative emotions than attachment and tends to decrease once a relationship begins. People who are not in a relationship often score higher on infatuation.

The word "infatuation" is sometimes used in everyday language to mean something different from "love." Hatfield argues that the only difference between infatuation and passionate love is the word used. Albert Ellis and Robert Harper found that people use "infatuation" to describe past relationships and "love" for current ones. Hatfield suggests that when people say someone is "just infatuated," they may be expressing disapproval of the relationship.

Passionate love is described as having an obsessional part, which includes thinking about the person a lot, feeling uncertain, and having mood changes. One study found that people in love often think about their loved one about 65% of the time they are awake.

Studies by Bianca Acevedo and Arthur Aron found that the PLS can separate obsessive and non-obsessive parts of passionate love. Obsessive questions on the PLS include:
• Feeling unable to control thoughts about the partner.
• Finding it hard to focus on work because of thinking about the partner.
• Feeling very sad when things go wrong in the relationship.

Non-obsessive questions include:
• Wanting the partner physically, emotionally, and mentally.
• Believing the partner is the perfect romantic partner.
• Preferring to be with the partner over anyone else.
• Feeling strongly attracted to the partner.

Acevedo and Aron found that obsessive passionate love was linked to higher relationship satisfaction in short-term relationships but lower satisfaction in long-term ones. A study by James Graham also found that obsessive romantic feelings were connected to lower satisfaction over time.

Acevedo, Aron, and Graham suggest that obsessive romantic feelings might be linked to attachment style. Attachment style refers to differences in how people think and behave in relationships, especially about security or insecurity. This includes anxiety (worrying the partner is not attentive) and avoidance (not wanting to rely on others). Some studies suggest attachment style forms in childhood, but others suggest it may be influenced by genetics. People can also have different attachment styles with different partners.

Idealization, or seeing the partner in the best possible light, is a type of positive illusion. A 1996 study found that couples who idealized each other were happier in their relationships. A brain scan study also found that couples who remained in love after four years showed brain activity linked to overlooking a partner's flaws.

While Hatfield and others have linked idealization to passionate love, studies on positive illusions have included couples at different stages of their relationships, including long-term couples.

Companionate love

Companionate love is not as intense as passionate love. It is more about gentle affection that happens when things are going well. Elaine Hatfield describes companionate love as "a steady burning fire, helped by happy experiences but stopped by sad ones." This type of love is more common in long-term relationships, and Hatfield says that having a compatible partner is important. Ellen Berscheid notes that companionate love may be the "staff of life" for many relationships and could be a better foundation for a satisfying marriage than romantic love.

Companionate love is connected to intimacy. Hatfield explains that close relationships often have these traits:

Companionate love is usually seen as the same as storge, but James Graham argues that storge is more like practical friendship, which lacks qualities such as intimacy and commitment that are part of companionate love.

Langeslag et al.'s Attachment Scale (similar to companionate love) includes questions about:

• Feeling that you can rely on the person you love.
• Being willing to share your things with the person you love.
• Feeling lonely without the person you love.
• Believing the person you love is the right one for you.
• The person knowing everything about you.
• Hoping your feelings for the person never end.
• Feeling emotionally close to the person you love.
• The person being able to comfort you when you are upset.
• The person being the one who makes you happiest.
• The person being part of your future plans.

Companionate love is sometimes compared to the "attachment" described in attachment theory. John Bowlby originally described an "attachment system" as a way to keep babies close to their caregivers, who act as a "secure base" for safety and exploration. When babies feel threatened, they seek closeness with their caregiver and feel upset when separated. A theory suggests this system is reused in adult relationships, as a new purpose for a trait that originally served a different function.

However, companionate love has also been described as similar to strong friendship. Ellen Berscheid points out that it is unclear whether all adult relationships are attachments in the way attachment theory defines them. She says the idea that romantic partners are each other's attachment figures needs more scientific testing.

Timeline

Love can develop in different ways. Some people experience strong, intense feelings quickly, such as in the case of love at first sight. However, not everyone feels this way. In a study involving people from China and the United States, 38% of participants said they fell in love quickly, while 35% said they fell in love slowly. In another study with people from Iran, 70% reported falling in love slowly or very slowly.

One theory suggests that intense, passionate love may change into a deeper, more lasting type of love called companionate love over time. However, other theories say that companionate love, which grows gradually, is also important at the beginning of a relationship. In some cases, companionate love may even come before passionate love. Research suggests that a strong emotional connection, or attachment, between partners may take about two years to form. For example, one study found that people who had been in a relationship for about two years were more likely to consider their romantic partner as someone they rely on, like a parent.

Studies estimate that passionate love may last between 18 months and 3 years. This idea comes from surveys collected by Dorothy Tennov for her 1979 book Love and Limerence. Another study from 1999, led by Donatelli Marazziti and others, found differences in blood chemical levels between people who were newly in love and those who were not. These levels returned to normal after 12 to 18 months. In rare cases, intense attraction can last much longer, such as in the case of long-term intense romantic love. People in these relationships often feel less obsessive over time compared to when they first began the relationship.

Companionate love is believed to grow stronger as a relationship continues, but it may slowly decrease over many years. In the past, some people thought companionate love remained steady once it developed. However, one study of newly married couples found that feelings of companionate love decreased after about one year.

Causal conditions

Many theories explain why people feel love for certain people and when they feel it. Most experts agree that passionate love and companionate love work in different ways.

Companionate love usually grows when people like each other and know each other well. However, the reasons for passionate love are more complex. Research shows that love and conflict can happen together in a relationship. Passionate love, in particular, may become stronger when negative emotions are present.

Ellen Berscheid explains that companionate love follows the "pleasure-pain principle." This means people tend to like those who make them feel good and dislike those who make them feel bad. Factors that influence companionate love include shared interests, knowing each other well, feeling respected, physical attraction, and sharing personal information. While passionate love often comes before companionate love, Berscheid notes that companionate love can also help develop passionate love.

Experts disagree about the role of sexual desire in romantic love.

Passionate love is often linked to sexual desire. For example, Berscheid suggests that passionate love may result from a mix of companionate love and sexual desire. However, Lisa Diamond argues that while sexual desire is often a cause of passionate love, it is not always necessary. Diamond supports her view with reports, historical examples, and an evolutionary idea that the brain systems involved in romantic love developed separately from sexual orientation. She believes spending time together and physical touch can replace sexual desire and help create romantic love between people of any sexual orientation.

Helen Fisher believes passionate love is connected to how animals choose mates. She says people have preferences that influence who they fall in love with, but these preferences are different from the sex drive, even though they are related.

Berscheid notes that emotional excitement, such as happy surprises, can lead to feelings of passion. Surprises and uncertainty are common in new relationships because partners are less predictable, which can create excitement.

Fisher suggests doing new and exciting activities together to keep passion alive. In an experiment by Arthur Aron and Christina Norman, couples who did an exciting task reported greater relationship satisfaction and romantic love compared to those who did a boring task.

Elaine Hatfield suggests that negative or mixed emotions can increase feelings of passion. She writes that passion involves physical excitement, and both good and bad experiences can create this excitement. Hatfield refers to studies showing that puppies who were sometimes rewarded and sometimes mistreated were more attached to their trainers than those who were treated consistently. She explains that predictable behavior creates little emotion, but unexpected changes—like a friend suddenly acting unkindly or an enemy showing kindness—can spark interest.

Another idea is that passion grows when intimacy increases quickly. Arthur Aron and Elaine Aron suggest that passion happens when a person rapidly expands their sense of self by including the qualities of their partner into their identity. These theories predict that passion decreases as relationships become more familiar and stable.

Love regulation is the process of using actions or thoughts to change how strong feelings of romantic love are. Sometimes, love feelings may be too strong, such as after a breakup, or too weak, such as in long-term relationships. Sandra Langeslag points out that it is a common belief that love feelings cannot be controlled, but research shows that controlling them is possible and helpful.

For example, looking at pictures of a loved one has been shown to increase feelings of infatuation (passionate love) and attachment (companionate love).

A technique called cognitive reappraisal involves focusing on positive or negative aspects of a partner, the relationship, or imagined future events:

• In negative reappraisal, someone focuses on negative traits of the partner ("he is lazy," "she is always late"), problems in the relationship ("we argue a lot"), or bad future scenarios ("he will cheat on me"). This can reduce feelings of infatuation and attachment but may lower mood temporarily. Langeslag suggests distraction can help improve mood in these cases. Negative reappraisal may help people deal with heartbreak or end harmful relationships.
• In positive reappraisal, someone focuses on positive traits of the partner ("he is kind," "she is spontaneous"), good parts of the relationship ("we have fun together"), or positive future scenarios ("we will live happily ever after"). This can increase attachment and improve relationship satisfaction, which may help strengthen long-term relationships.

Love regulation does not change feelings instantly. Langeslag recommends practices like writing down thoughts daily to create lasting changes in love feelings.

Biology

Passionate and companionate love are connected but different. They use different parts of the brain and have different roles. Passionate love is believed to help people choose a partner or start a close relationship. Companionate love helps keep a relationship strong, keeps people close, and encourages friendly actions.

Passionate love is often linked to a brain chemical called dopamine. Companionate love is often linked to a hormone called oxytocin, and sometimes to another hormone called vasopressin or to chemicals called endogenous opioids.

Passionate love is sometimes compared to addiction, but there are differences. People in the early stages of romantic love may feel similar things to addicts, such as happiness or strong desires for their partner. However, these feelings usually fade over time, while addiction usually gets worse. Helen Fisher has suggested that romantic love can be a "positive addiction" when it is mutual, but a "negative addiction" when it is not returned or is not appropriate.