Sibling relationships can be important and influential throughout the lifespan. During childhood, siblings can influence both personality development and behavior. In adulthood, siblings can be an important source of friendship, support, and information. In old age, siblings are often an important source of both emotional and tangible support. Although much is known about the effects of birth order, family size, and sex differences on intellectual and personality characteristics (Cicerilli 1995), less is known about sibling communication and interaction patterns. Sibling interaction is guided by a set of characteristics that, as a whole, are unique to the sibling relationship.
Characteristics Of Sibling Relationships
There are six different characteristics that together make the sibling relationship unique. It is pervasive, involuntary and permanent, relatively egalitarian, typically includes a long shared history, is often filled with paradox, and comes in a number of different forms based on family makeup.
First, the sibling relationship is pervasive in both its longevity and the number of people who have siblings. A 1998 general social survey reported that 96 percent of American adults have at least one sibling (National Opinion Research Center 1998). The sibling relationship is the longest-lasting relationship in many people’s lives, as siblings often stay connected with one another throughout childhood, adulthood, and old age. Further, researchers have estimated that around 80 percent of the population spends at least one third of their lives with their siblings (Fitzpatrick & Badzinski 1994).
Second, the sibling relationship is both involuntary and permanent. It is involuntary because it is not a relationship of choice like a friendship. It is permanent because even though siblings might choose to disengage from an active relationship, their relationship status as siblings cannot be dissolved (Cicirelli 1995).
Third, the sibling relationship is relatively egalitarian in nature. It is more egalitarian than other family relationships, such as the parent–child relationship (Cicirelli 1995), and becomes still more so as the siblings move out of childhood and adolescence. One reason that siblings, especially in adulthood, can interact as equals is that they typically have similar feelings of acceptance for one another.
Fourth, siblings share a long family history. Siblings’ shared history is different than a shared history with friends because it includes management of sibling rivalry and conflict, parents’ equal or differential treatment of siblings, and specific parent–child relationships.
Fifth, the sibling relationship can be filled with paradoxical feelings and interactions. In many sibling relationships competition, conflict, and rivalry may exist alongside feelings of love, care, and support (Mikkelson 2005).
Finally, one of the most distinctive characteristics of the sibling relationship is that it exists in a number of different forms, based on common biological origin and legal relationships. Siblings that have both parents in common can be identical twins, with 100 percent genetic relatedness; fraternal twins, with approximately 50 percent genetic relatedness; or full siblings, again with approximately 50 percent genetic relatedness. Siblings that have one parent in common are half siblings, with approximately 25 percent genetic relatedness. Other, legally defined sibling relationships are stepsiblings and adopted siblings. Stepsiblings share neither parent in common, whereas adopted siblings may be related (as in the case of parents adopting a niece or nephew) or may not.
Most sibling research has examined full biological siblings. Thus, less is known about relationships such as adopted siblings, stepsiblings, and half siblings. This is unfortunate, as the Stepfamily Association of America (2006) estimated that at some point, 30 percent of children will live in a stepfamily (this estimate included children who live with a cohabiting parent). Further, in European nations, researchers have estimated that stepfamily rates are as low as 4 percent in some countries and as high as 38 percent in others (Prskawetz et al. 2003). In addition, the 2000 US Census reported that 2.5 percent of children under the age of 18 were adopted (Kreider 2003). Although stepsiblings, adopted siblings, and half siblings are quite frequent in their occurrence, less is known about the communication patterns of these relationships.
Researchers have studied three aspects of sibling interaction in particular: sibling contact, sibling conflict and rivalry, and sibling support. Because siblings live together during the childhood and adolescent years, sibling contact is relatively high. However, as siblings move out of the household to attend college or to live on their own, the frequency of contact between siblings is greatly reduced because they do not share a living space (Leigh 1982). Not sharing a living space can also reduce contact between siblings because interaction with a sibling becomes more of a personal choice. Contact between siblings often tends to decline as siblings move into middle adulthood, as they become preoccupied with their own marriages and families. However, Leigh (1982) found that as siblings move into the later stages in the lifespan, sibling contact increases. Generally, the contact patterns between siblings can be represented by an hourglass figure, with contact patterns being the highest in youth and old age and the lowest during the middle stages of adulthood.
Researchers have examined the factors that predict the extent to which siblings remain in contact with one another. Lee et al. (1990) found that siblings who were emotionally close, felt responsibility for one another, had an expectation of contact, and were geographically close to one another were most likely to stay in frequent contact. The most important of these variables appears to be emotional closeness, as contact patterns between siblings are highly related to feelings of closeness between them (Cicirelli 1995).
Contact patterns between siblings are also influenced by the type of relationship they share. White and Riedmann (1992) found that contact was greater among full biological siblings than it was between half siblings and stepsiblings. Mikkelson (2006) found that, comparing types of sibling relationships, contact was more frequent between twins and full siblings than between half siblings and stepsiblings. Further, adopted siblings’ contact patterns were similar to those of full siblings.
Rivalry And Conflict
Although rivalry between siblings starts in childhood and adolescence, there are conflicting research findings with respect to whether rivalry decreases with age or stays relatively stable. Cicirelli (1995) noted that rivalry decreases as siblings age, so that when siblings reach late adulthood, rivalry is minimal. However, other studies have found that that feelings of rivalry often persist even into old age. Cicirelli (1995) argued that these inconsistent findings might be due to the fact that when older siblings still have feelings of rivalry, they often do not express these feelings overtly. Thus, feelings of rivalry between siblings may exist well into adulthood; however, expressed rivalry may decrease as siblings have developed ways of interacting in which the rivalry and conflict do not become explicit.
Rivalry often begins in sibling relationships when siblings compete for such resources as love, affection, admiration, and money from their parents. Although all siblings probably experience some feelings of rivalry, these feelings can be intensified or diminished depending on whether the siblings are treated relatively equally and how much they are vying for the same resources. When siblings express feelings of rivalry and jealousy, they tend to express them in a distributive way (arguing, yelling, or making hurtful comments) instead of an integrative way (disclosing feelings, discussion; Bevan 2004). Siblings are more likely to express rivalry or any other type of conflict in a negative way, due to the permanent nature of the relationship.
Among the different types of sibling relationships, while feelings of rivalry may or may not be higher among half siblings and stepsiblings than among full siblings, half and stepsiblings did report a higher percentage of actual conflict than did full siblings (White & Riedmann 1992).
Siblings can be an important source of support for each other throughout the lifespan. Goetting (1986) argued that the primary developmental task of siblings during early adulthood is to provide companionship, emotional support, and direct aid to one another. During middle adulthood siblings are relied upon for support, particularly in times of crisis. Siblings’ support might be most frequent and important in old age. Cicirelli (1995) found in a study of hospitalized elders that sibling support was second in importance only to support from spouses.
Sibling support is predicted primarily by the amount of contact siblings share and their feelings of closeness to one another (Cicerilli 1995). Similarly, Mikkelson (2006) found that the amount of all five types of social support given (emotional, esteem, informational, network, and tangible) was positively related to the amount of closeness siblings felt. Further, Mikkelson (2006) found that the amount of social support siblings gave to one another was related to their relationship type. Specifically, identical twins gave the most social support, followed by fraternal twins and full siblings, followed by half siblings, with adopted siblings and stepsiblings giving the least.
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- Mikkelson, A. C. (2006). Differential solicitude of social support in different types of adult sibling relationships. Unpublished doctoral dissertation, Hugh Downs School of Human Communication.
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- White, L. K., & Riedmann, A. (1992). When the Brady bunch grows up: Step/half- and fullsibling relations in adulthood. Journal of Marriage and the Family, 54, 197–208.