Young and Middle Adulthood 23belongings. These functions correspond to the assumed underlying psychological
dimensions of friendships: emotional closeness and reciprocity of support (Clark &
Mills, 1979; Neyer, Wrzus, Wagner, & Lang, 2011).
Emotional Closeness and Reciprocal Support in Friendships
Friendships are typically emotionally close and reciprocally supportive relation-
ships. At the same time, an individual’s friendships often differ in their qualities
(e.g., emotional closeness, Neyer et al., 2011). Namely, people feel varying degrees
of closeness among their various friends. The emotional closeness to friends often
relates to how similar they are in their interests, values, and personality traits
(Floyd, 1995; Montoya, Horton, & Kirchner, 2008; Morry, 2007; Suitor, 1987).
The similarity- attraction theory (Byrne, 1971) suggests that people seek out similar
others as friends to validate their own self- and worldviews. As a result, interacting
with similar others who share one’s worldview is pleasant because one’s self- and
worldviews are confirmed (Reis & Shaver, 1988). Multiple pleasant interactions
then also lead to perceiving the relationship with the other person as pleasant,
resulting in feeling close to the other. Hence, similarity predicts emotional close-
ness among friends (Montoya et al., 2008). However, effects of similarity on close-
ness and liking in friendships are strongest for perceived similarity. Accordingly,
Montoya and Horton (2013) refined the explanations for the similarity- attraction
link stating that liking results from ascribing one’s own positive characteristics
to the other person (i.e., perceiving him/ her as similar to oneself and one’s posi-
tive characteristics). As a result, people with (assumed) positive characteristics
are viewed more positively, that is, are liked better (Kaplan & Anderson, 1973;
Montoya & Horton, 2013).
Another psychological dimension of friendships concerns the exchange of sup-
port. Overall, people aim for fairness in friendships. The general rule of reciprocity
(Gouldner, 1960) applies to friendships as well, leading to long- term reciprocity of
provided and received support. However, reciprocity of support also varies some-
what between friendships, for example, depending on the relationship duration.
During the formation of friendships, people reciprocate favors and support quickly
to avoid the impression of exploiting the other person (Lydon, Jamieson, & Holmes,
1997). In established friendships, however, such tit- for- tat behavior (immediate
reciprocation; Axelrod & Hamilton, 1981) is detrimental as people value balanced
relationships, but they avoid keeping detailed track of costs and benefits (Clark,
1984; Lydon et al., 1997; Silk, 2003).
Individual Differences in Friendship Networks
In addition to qualities of friendships differing within people, such as emo-
tional closeness or reciprocity of support, friendships can differ between people.