Studying attraction, relationships and love can be a challenge because it is not always possible to make use of an experimental design. A lot of research is been done using speed dating sessions, but there is a lack of cross-cultural research.

Attraction is based on an alluring face, a pleasant interaction or the perception of similarity. Attractive people are rated better on other characteristics. Physical attractiveness is a powerful first cue to who we might like.

Faces and bodies that are symmetrical are judged to be more attractive and likeable. A clear rosy skin, average weight and shiny hair also seem to signal good health and are thus rated as more attractive. People that look like they have access to adequate resources (e.g: money) are deemed more attractive. Men living in a culture with scarce resources find heavier women more attractive. There are also strong individual differences in what we deem attractive because judgements of attractiveness are influenced by our experience and expectations. Liking increases perceived physical attractiveness and perceived physical attractiveness increases liking.

The more similar people are, the more they like each other. It is greater if the qualities we share are important to us and salient. Similarity helps us move from attraction to liking for several reasons:

1. Similarity signals who is “me and mine”
   People tend to view their own characteristics as desirable. Similarity is a significant cue to in-group membership. We also like people more who like us.
2. Similarity signals familiarity
   Similarity and feelings of familiarity are intertwined and familiarity leads to an increase in liking.
3. Similarity contributes to mastery
   Similarity is a key predictor of cooperation, trust and helping increases the rewards of interaction with similar others and again increasing liking. People tend to interact with similar others.
4. Similarity validates connectedness
   Similarity gives us a sense of connection with others.

People are attracted to those with whom they have positive interactions. Physical proximity promotes frequent interaction. There are several reasons why interaction leads to increased liking:

1. Interaction makes others familiar
   The more we interact with people, the more similar they seem.
2. Interaction contributes to mastery
   If interaction with someone is rewarding we tend to like them more.
3. Interaction helps us feel connected
   The sense of relatedness and attachment is a reward of interaction and this can help us feel connected to the other person.

If interaction fails to meet our needs or harms us it leads to disliking. Acquaintanceship will progress toward friendship when liking, attractiveness, similarity and interaction become mutually reinforcing processes.

Friendship develops through interactions that fulfil mastery and connectedness needs. The rewards that each partner gets from interaction are key in determining the course of the relationship. Exchange relationships refer to relationships in which people offer rewards in order to receive benefits in return. Uncertainty and anxiety may cloud both partners’ feelings about the transition.

Self-disclosures include facts about one’s life and situation, as well as inner thoughts, feelings and emotions. Self-disclosure makes people like you more. Those who disclose more than is appropriate for the closeness of the relationship make people uncomfortable. Women self-disclose more than men. The difference is largest in same-sex friendships. Reacting to disclosures with sympathetic concern is a crucial means of building greater intimacy and closeness in relationships.

A close relationship is a relationship involving strong and frequent interdependence in many domains of life. Interdependence in a relationship means that each partner’s thoughts, emotions and behaviours influence the other’s. Love refers to thoughts, feelings, and actions that occur when a person wishes to enter or maintain a close relationship with a specific person. Close relationships involve three forms of interdependence.

Cognitive interdependence refers to thinking about the self and the partner as parts of a whole. Partner knowledge becomes self-knowledge. The closer the relationship, the slower the responses that require differentiation of the two partners. The self-serving bias becomes applicable to the partner if the relationship is close.

Behavioural interdependence means that each person has a great deal of influence on the partner’s decisions, activities and plans. Close relationships include rewards that benefit the relationship itself. Communal relationships refer to relationships in which people reward their partner out of direct concern and to show caring. When people make decisions and take action that reflects the other rather than the self, relationships tend to endure over time.

Affective interdependence refers to the affective bond that links close relationship partners. Each partner’s emotional well-being is deeply affected by what the other does. Intimacy is a positive emotional bond that includes understanding and support. Intimacy develops through self-disclosure (1), acceptance, acknowledgement and understanding in the response (2) and increased responsiveness (3). Social support refers to emotional and physical coping resources provided by other people. Believing that you have social support can induce the effects of social support. Commitment refers to the combined forces that hold the partners together in an enduring relationship. Commitment emerges from personal satisfaction (1), realization that equivalent rewards would not be available in alternative relationships (2) and the number of barriers that make leaving the relationship difficult (3).

Attachment styles are people’s basic securely attached, avoidant or anxious orientation toward others in close relationships. There are four attachment styles in close relationships:

1. Securely attached individuals
   Feel good about themselves and are unafraid of intimacy
2. Dismissing individuals
   Feel good about themselves, but do not trust others. They avoid intimacy and are not worried about the lack of it.
3. Preoccupied individuals
   They want to be intimate with others but worry that others don’t want that.
4. Fearful attached individuals
   Anxious about abandonment and a fear of intimacy.

Romantic love involves sexual feelings, a sense of intense longing for the partner, euphoric feelings of fulfilment and ecstasy when the relationship goes well and anxiety and despair when it does not. Passion is linked to a set of beliefs about the beloved and motivations for specific types of action.

Signs of good health and access to resources aren’t equally important to everyone all the time. Reproduction has a higher cost for women than for men, so men try to reproduce as often as possible, so it is important for men to focus on physical cues and since the investment for women is bigger, they tend to focus on resources.

External factors also place stresses on relationships. Depression and anxiety may arise from the threatened loss of the valued relationship and anger may arise due to the loss of self-esteem from being rejected by the partner in favour of someone else. Problems in a relationship can lead to a cycle of dissatisfaction and decline.

Accommodation is the process of responding to a negative action by the partner. Constructive accommodation involves actions that help maintain the relationship, including actively discussing problems. There are four problematic types of communication that can foreshadow the end of a relationship: criticism beyond complaining about a specific event (1), a lack of respect (2), defensiveness (3) and stonewalling (4), which is withdrawing from the interaction. There are different resources for constructive accommodation:

1. Attachment style
   Couples with secure attachment styles tend to accommodate more positively than other couples.
2. Commitment
   Constructive accommodation is more likely when people are committed to the relationship.
3. Idealization of partner and relationship
   Idealization of the partner leads to less conflict.
4. Beliefs about relationships
   The belief that relationships are the result of hard work can help relationships last longer.

If attempts to respond constructively to relationship threats fail, conflict escalates.

The more depressed, lonely and unhappy one partner felt after the break-up, the less the other partner did. Attributing the break up to the other person may protect the self. People who attribute the cause of a divorce to the relationship rather than to themselves tend to adjust better. The death of a spouse is regarded as the most stressful major life event. Loneliness is an emotion arising from unmet needs for affection and self-validation from a psychologically intimate relationship. Lonely individuals become increasingly focused on social threats and the possibility of rejection until they hold negative social expectations for themselves and begin to behave in ways that confirm their negative views of themselves.