Long-Lasting Friendships 277expectation of mutual aid, supportive behavior, and “assumed bonds of investment,
commitment, and reward dependability which fulfill a friend’s needs” (p. 203).
Rusbult’s relationship investment model (Rusbult, 1980, 1983) has provided a use-
ful framework for understanding these components of friendships and the friend-
ship maintenance processes. The relationship investment model proposes that
friendship satisfaction is a function of the rewards (positive aspects of the relation-
ship) minus the costs of the relationships. Furthermore, commitment to the friend-
ship is reflected by the satisfaction, plus the investments (what would be lost if the
relationship were to end) minus the alternatives (the other things that could be
done if the relationship were not in existence). Branje and colleagues (2007) dem-
onstrated in a longitudinal study of adolescents that the investment model predicted
stability in friendship as well as the tendency to switch best friends. Furthermore,
satisfaction, investments, and alternatives predicted friendship commitment both
concurrently and over time.
Friendship maintenance behaviors appear to be engaged in a manner consistent
with the predictions of the investment model framework (Rusbult, 1980, 1983).
Friends’ usage of maintenance behaviors of support, openness, and interaction
positively correlates with relationship satisfaction and commitment (Oswald et al.,
2004). Further, the maintenance behaviors correlate positively with rewards and
negatively with relationship costs. Likewise, maintenance behaviors positively cor-
relate with investments and negatively with alternatives to the relationship. In sum,
maintenance behaviors are associated positively with rewards and investments that
support relationship satisfaction and commitment but negatively with costs and
alternatives, which negatively contribute to satisfaction and commitment.
The underlying motivation of the use of the maintenance behaviors may also
play a role in how the maintenance behaviors correlate with the investment model
variables. Mattingly, Oswald, and Clark (2015) studied 115 friendship dyads and
asked them to report on their own as well as perceptions of the friends’ use of main-
tenance behaviors. However, they also asked the friends to report on how often the
behaviors were used strategically (with specific intention to obtain a desired result
from the friendship) and routinely (without specific intention to obtain a desired
result from the friendship). The results of the study indicated that an individual’s
self- reported own use of routine maintenance behaviors correlated with their self-
reported friendship satisfaction, commitment, rewards, and investments. In con-
trast, the individual’s self- reported strategic use of the maintenance behaviors was
correlated with friendship costs and commitment but negatively associated with
rewards. Perceptions of the friend’s use of routine behaviors was positively asso-
ciated with one’s own friendship satisfaction, rewards and investments, but nega-
tively associated with friendship alternatives. In contrast, perceptions of the friend’s
use of strategic friendship maintenance was negatively associated with satisfaction,
costs, commitment, and investments and positively associated with friendship
alternatives.