Social comparison theory suggests that people tend to compare themselves with someone similar to themselves rather than with someone divergent in opinion and ability. Because the gender-based role pattern in marital relationships was dominant until recently in Western society, individuals probably compared their marital inputs and outcomes mainly with those of same-sex others in some reference group, since same-sex others were considered to be more similar than the spouse with regard to roles, duties, needs, and preferences.
Social comparison may reveal that one's performance level or reward outcome is inferior or superior to that of the comparison person. In these instances comparison may be affected by the discrepancies such that subsequent behavior may be adjusted in accord with the direction as well as the magnitude of the discrepancy.
Research indicates that upward comparisons can be both self-enhancing and self-deflating, depending on how the comparisons are construed by the individual (Collins 1996). In general, however, downward comparisons tend to be self-enhancing while upward comparisons are generally threatening to well-being and self-esteem (Lyubomirsky and Ross 1997). It is possible that a feedback loop develops between enduring happiness, transient self-esteem and response to social comparison (Lyubomirsky and Ross 1997).
The tendency to evaluate the self and the yearning to transform dissatisfactory features of the self are considered normal characteristics of the adolescent period (Douvan & Gold 1966). Similarly, social comparison with peers is typical of adolescents, for whom the peer group provides a source of norms and values for appropriate appearance, behavior, and social activities (Ausubel, Montemayor, & Svajian 1977; Coleman 1980).
Brickman and Bulman (1977) suggest that, although social comparison may have potential for self-enhancement, it is often avoided because of the damage it may cause to one's own and others' self-esteem. For example, children who look at their peers' work for self-assessment purposes may be dismayed to learn that they have completed considerably less of the assignment than their peers.
The group behavior of boys included more physical aggression following negative social comparison than the other treatments, and their group behavior also consisted of more nonverbal teasing behavior following the negative comparison treatment than that of the equal and nonsocial comparison groups. When the behavior of the nontarget partners was controlled, children initiated more physical aggression, nonverbal teasing, and regression after experiencing negative social comparison with the partners than after following the other treatments.
Social comparison increases the stability of one's evaluation and offers an occasion for expressing affection and other interpersonal rewards [8,9]. Jones and Gerard  propose that the motivation for social comparison leads the individual to choose reference groups to make such comparisons. They suggest that, in many social comparison situations, one is more likely to compare oneself with an individual (or group) who is "at about the same level" on given attributes than with an individual who is either greatly superior to or greatly inferior to oneself on the given attributes.
The concept of social comparison was broadened in this study to include nonevaluative comparison activity aimed either at differentiating self from other or identifying self with other. Not only does one engage in social comparison for the purposes of self-evaluation, which Festinger recognized, but also to address the persistent issue of how each of us is the same but different from everyone else, a unique individual and simultaneously a member of the shared human community.
People often make comparisons in their daily lives. Even when watching commercials on TV, people have tendency to compare themselves to the models in the ads (Martin & Kennedy, 1993). However, there was inconsistent support for using highly attractive models in past marketing literature. For example, Bower (2001) showed that highly attractive models included in advertising could destroy the advertising effectiveness because of the deflated self-image in contrast to the beautiful ad models.
Comparing the self with others, either intentionally or unintentionally, is a pervasive social phenomenon. Perceptions of relative standing can influence many outcomes, including a person's self-concept, level of aspiration, and feelings of well-being (i.e., subjective well-being). Just as comparison of objects and symbols is a core element of human conduct and experience, so too is interpersonal comparison. In his seminal theory of social comparison, Festinger (1954) hypothesized that other people who are similar to an individual are especially useful to that individual in generating accurate evaluations of his or her abilities and opinions (i.e., in serving the self-evaluation motive).