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Friendships in Young
and Middle Adulthood
Normative Patterns and Personality Differences
Cornelia Wrzus, Julia Zimmermann, Marcus Mund,and Franz J. NeyerFriendships are important throughout people’s lives. From childhood to old age,
most people have friends. Yet, why do people differ in how many and what kinds
of friendships they have? Furthermore, how do friendships change throughout
people’s lives? And how do friendships change people’s personality? Answers to
these questions would provide a deeper knowledge of individual differences and
normative changes in friendships and thus help to understand how friendships
can contribute to well- being and health (Adams & Blieszner, 1995; Pinquart &
Sörensen, 2000).
In their daily lives, people frequently use the term “friend” to describe a broad
range of individuals with whom they maintain relationships, such as close acquain-
tances, family members, spouses, or coworkers. However, most scientific defini-
tions of friendships concur on the following aspects that describe friendships and
distinguish them from other relationships such as family relationships or romantic
partners: Friendships are voluntary, informal peer relationships that rest on reci-
procity, possess a positive quality (i.e., they are perceived as being pleasant), and
(often) do not contain open sexuality (Argyle & Henderson, 1985; Blieszner &
Roberto, 2004; Hartup & Stevens, 1997). In contrast to family relationships, friend-
ships are voluntary regarding choice and formation, not based on kinship or legal
arrangements. In contrast to professional relationships with coworkers, supervisors
at work, or service staff, friendships are informal, personal, and largely without a
(direct) hierarchy, whereas professional relationships are often based on contracts
and regulations. In the present chapter, we focus on friendships in young and middle
adulthood (i.e., approximately between 20– 40 years and 40– 60 years, respectively).