In psychology, a distinction is often made between two basic types of love:
Passionate love, also called romantic love and infatuation, is "a state of intense longing for union with another. Reciprocated love (union with the other) is associated with fulfillment and ecstasy; unrequited love (separation) is associated with emptiness, anxiety, or despair", and "the overwhelming, amorous feeling for one individual that is typically most intense during the early stage of love (i.e., when individuals are not (yet) in a relationship with their beloved or are in a new relationship)". Companionate love, also called attachment, is "the affection we feel for those with whom our lives are deeply entwined", and "the comforting feeling of emotional bonding with another individual that takes some time to develop, often in the context of a romantic relationship".
Evolutionary theories state that these two types of love have different purposes, and scientific research suggests they follow somewhat different mechanics. Both passionate and companionate love can contribute to relationship satisfaction.
Passionate love is commonly referred to as "romantic love", especially in biology; however, "passionate love" is most common in psychology. The meaning of "romantic love" is more complicated to define, because of its cultural history and other connotations.: "English dictionaries distinguish 'romantic' with several definitions, but in reality, such tidy divisions are misleading. When we use the word, these different meanings bleed into each other." (p. 87); "The cultural history of 'romance' and various meanings of the word 'romantic' make it extremely difficult to define 'romantic love'. Academic psychology—usually quite pedantic about its terminology—has been unable to establish a consensus. Some psychologists use the term in accordance with its courtly origins, whereas others use it interchangeably with 'passionate love'. As a culture, we seem to have settled on the latter usage, viewing 'romantic love' and 'falling in love' as much the same thing." (p. 106) Academic literature on love has never adopted a unified terminology. Other terms associated under the heading of passionate love are being "in love", having a crush, lovesickness, obsessive love, limerence and eros.
Companionate love has been compared to strong liking, friendship love, and the "attachment system" from attachment theory, but contention exists over these relations.
A further category distinguishable from these includes compassionate love, agape and unconditional love: that of love focused on caring about others.
Passionate love
Passionate love feelings are most commonly measured by psychologists with a questionnaire called the Passionate Love Scale (PLS). In the PLS form, Elaine Hatfield & Susan Sprecher specify the components of passionate love as:Hatfield, E. & Sprecher, S. The passionate love scale. In Fisher, T. D., C. M. Davis, W. L. Yaber, & S. L. Davis (Eds.) Handbook of sexuality-related measures: A compendium (3rd Ed.). (pp. 466-468). Thousand Oaks, CA: Taylor & Francis.
Passionate love is linked to passion, as in intense emotion, for example, joy and fulfillment, but also anguish and agony. Hatfield notes that the original meaning of passion "was agony—as in Christ's passion." Rather than being an emotion itself, passionate love is said to be a motivational state which produces different emotions depending on the situation (e.g. joy when requited, and sadness when unrequited).
Passionate love is said to be present (or the most intense) when a relationship is new, or before a relationship has started.
Companionate love
Companionate love is less intense than passionate love, and feels more like gentle affection when things are going well in a relationship. Companionate love is also linked to intimacy, and Hatfield suggests intimate relationships have these characteristics:
Companionate love is more about long-term relationships; as such, partner compatibility is emphasized as important. Ellen Berscheid says that companionate love might be "the staff of life for many relationships" (rather than passionate love), and more beneficial to marital satisfaction.
Relation to other concepts Passionate and companionate love, as envisioned by Elaine Hatfield, was an attempt to unify a variety of different taxonomies, based on a recurring distinction identified by her. The headings are intentionally broad, and subsume many of the differences found in more precise taxonomies. For example, among the love styles developed by John Alan Lee, Hatfield considers both eros and mania under "passionate love", and both storge and pragma under "companionate love". Later research identified issues with this broad classification.
Passionate and companionate love are also referred to by researchers using the terms "infatuation" (for passionate love) and "attachment" (for companionate love). However, these terms carry other connotations, and there is contention over their relation.
Infatuation
Colloquially, infatuation suggests irrationality and capriciousness. "Infatuation" is sometimes contrasted with "love" in a "love versus infatuation" distinction, although it has been argued this kind of distinction is semantic. According to Elaine Hatfield:
Hatfield says that "romantic love" is used by lovers for relationships which are still in progress, and "infatuation" for relationships which become terminated; the distinction might therefore be only identifiable in hindsight. When parents or friends say somebody is "just infatuated" also, they are actually just expressing disapproval.
In the triangular theory of love, by Robert Sternberg, "infatuation" refers specifically to romantic passion in the absence of intimacy and commitment, which departs from Hatfield's idea that there is no difference. Sternberg has likened his idea of infatuation to limerence.
Attachment theory
In its original conception by Elaine Hatfield, companionate love is compared to liking (or affection), with the only real difference being the depth of one's feelings and degree of their involvement. Passionate love is distinguished from these as a state of longing and arousal, which does not seem to follow the laws of liking (for example, seemingly being amplified by negative emotion).
As attachment theory became a prominent framework for explaining adult pair bonds, a contention arose among researchers over how passionate and companionate love relate to the "attachment system" from attachment theory. The attachment system was originally conceived of by John Bowlby as a system evolved to keep infants in proximity of their caregiver (or "attachment figure"). The child uses the attachment figure as a "secure base" to feel safe exploring the environment, seeks proximity with the attachment figure when threatened, and suffers distress when separated. A prominent theory suggests this system is reused for adult pair bonds, as an evolutionary exaptation or co-option, whereby a given trait takes on a new purpose. Adults in romantic or intimate relationships exhibit attachment behaviors with their partners (e.g. proximity seeking, safe haven, separation distress, etc.) which are similar to children with their parents.
In a version of this theory from romantic love researchers in the 2000s, the attachment system became synonymous with companionate love, as in Helen Fisher's popular theory of independent emotion systems. A different opinion, by Ellen Berscheid in 2010, also considered companionate love in its original sense (of strong liking or friendship). According to Berscheid, whether all adult relationships are "attachments" in the sense meant by attachment theory was unproven, and such an assumption was "in dire need of empirical scrutiny."
Initially, it was believed that an attachment bond takes about two years to form, and that such attachment functions play little to no role in new relationships until this occurs. However, later research indicated that the attachment system is in fact active during the early stage of romantic love. A series of studies by Paul Eastwick and Eli Finkel demonstrated that attachment anxiety motivated proximity seeking, with behaviors directed towards relationship formation, even in study participants who were not in a relationship. Furthermore, this "partner-specific" attachment anxiety was distinguishable from the anxious attachment style, and it was associated with an increase in passionate love. The attachment system is also believed to be associated with oxytocin, which has been found circulating in people experiencing the early stage of romantic love.
A newer theory then states that passionate love also involves the attachment system, but with additional brain systems for its other features (intense attraction, obsessive thinking, and so on). A further implication is that passionate love is actually distinct or independent from sexual desire. If passionate love was co-opted, then its evolutionary antecedent did not involve a sexual preference (i.e., parents should not only bond with an opposite-sex child). This is used to explain, for example, instances of "platonic" infatuations (without sexual desire) between schoolgirls, and romantic friendships between otherwise heterosexual men.
Friendship
A further contention is how companionate love relates to friendship. For example, historically, the love styles storge and pragma have been labeled as companionate love. Of these, storge is named after the Ancient Greek "storge", and refers to a relationship style in which love grows out of a special friendship, or at least mutual activities shared between the sort of people who could have been old friends. A more passionate lover might consider storge to be "just friendship or affection, not love". In pragma, a partner is chosen based more on demographic or personality traits, and shared activities are more of a means to an end.
A different definition comes from the triangular theory of love, by Robert Sternberg, where "companionate love" refers to features of intimacy and commitment in the absence of passion. (With the addition of passion, it becomes labeled "consummate love".)
In light of this, a meta-analytic factor analysis found that the love attitudes for storge and pragma did not align with intimacy and commitment from the Triangular Love Scale, but rather on a separate factor of their own (labeled "practical friendship"). Intimacy and commitment aligned on a general love factor, along with measures such as passion and Zick Rubin's liking scale. Therefore, it is concluded that while practical friendship has some aspects of companionate love, the two can be considered distinct.
Obsessive and harmonious passion
Research has identified issues with the notion that romantic passion only takes a single form, as was assumed in Elaine Hatfield's original conception of passionate love. The dualistic model of passion (DMP) is a theory invented by the psychologist Robert Vallerand which suggests that passion can be split into two components, termed "obsessive" and "harmonious" passion:
In obsessive passion, a person's passion is driven by internal pressure, controlling them and interfering with other aspects of their life. In harmonious passion, the person experiencing it retains their autonomy, and their passion is more in harmony with other life domains.