Research indicates that mere repeated exposure to another person facilitates attraction. We tend to be attracted to people who are similar to us socially (age, race or ethnicity, economic status) and psychologically (attitudes, interests). In first impressions, we are most attracted to people who are physically attractive; we also tend to be attracted to people whom we believe to be "within reach" of us, depending on our sense of our own attractiveness or desirability. Playing hard to get seems to work only if the person does so selectively.

According to reinforcement theory, we are attracted to those who give us many reinforcements. Interaction with people who are similar to us is smooth and rewarding; they have similar outlooks and like the same things we do. According to sexual strategies theory, we prefer young, attractive people because they are likely to be healthy and fertile. Men prefer women who are sexually faithful (hard to get); women prefer men with resources who will invest in them and their children.

Intimacy is a major component of a romantic relationship. It is defined as a quality of a relationship characterized by commitment, feelings of closeness and trust, and self-disclosure.

According to the triangular theory, there are three components to love: intimacy, passion, and decision or commitment. Love is a triangle, with each of these components as one of the points. Partners whose love triangles are substantially different are mismatched and are likely to be dissatisfied with their relationship.

According to the attachment theory of love, adults vary in their capacity for love as a result of their love or attachment experiences in infancy. This theory says that there are three types of lovers: secure lovers, avoidant lovers, and anxious-ambivalent lovers.

Love can also be viewed as a story, with characters, a plot, and a theme. People use their love stories to interpret experiences in relationships. Falling in love happens when a person meets someone who can play a compatible role in his or her story.

Love may have a neurochemical component. Passionate love, a state of intense longing and arousal, may be produced by dopamine. Like all chemically induced highs, passionate love eventually comes to an end. It may be replaced by companionate love, a feeling of deep attachment and commitment to the partner. This type of love may be accompanied by elevated levels of prolactin and oxytocin, which may be produced by physical closeness and touch.

Hatfield and Sprecher have constructed a scale to measure passionate love. Such scales make it possible to do scientific research on complex phenomena like love. Scores on this scale were correlated with measures of commitment to and satisfaction with romantic relationships. Research indicates that, in general, men are more romantic than women and fall in love earlier in a relationship.

Berscheid and Walster have hypothesized that there are two basic components of romantic love: being in a state of physiological arousal and attaching the label "love" to the feeling. Several studies report evidence consistent with the hypothesis.

Cross-cultural research indicates that individualistic cultures like that of the United States emphasize love as the basis for marriage and encourage intimacy between partners. Collectivist cultures emphasize intergroup bonds as the basis for marriage, and discourage intimacy between partners. Culture influences the importance of various characteristics in choosing a mate; it also affects our standards of beauty and the likelihood that we would marry someone we didn't love.