The findings we have presented provide evidence that mothers' favoritism, as perceived in adulthood and recalled from childhood, affects the quality of sibling relations in adulthood, similar to studies of sibling relations in childhood (
Brody et al., 1994;
McHale et al. 1995;
Suitor et al., 2008). In fact, recollections of favoritism from childhood was the only factor that affected both closeness and conflict among siblings. Despite the fact that individuals tend to avoid conflict and increase harmony in their relationships as they move across the life course (
Charles & Carstensen, 2008;
Coats & Blanchard-Fields, 2008;
Lefkowitz & Fingerman, 2003), siblings appear to have difficulty ignoring their mothers' favoring particular siblings in the family. Further, mothers' favoritism appeared to reduce closeness regardless of which child was favored, suggesting that siblings' relationships are shaped more by principles of equity than by social comparison. The analysis also indicated that recollections of favoritism from childhood had more consistent effects on sibling relations than did perceptions of current favoritism; current favoritism predicted only closeness, whereas recollections from childhood affected both closeness and conflict.
Although additional research is needed to explain this pattern, there may be two related processes that can explain the differential effects of current and childhood favoritism. First, adult siblings may attempt to maintain harmony, despite negative feelings emanating from perceptions that their mothers currently favor another child. As we have discussed at several points in the paper, as individuals move through adulthood, they place greater emphasis on maintaining harmony in their relationships. However, this does not mean that they are not affected emotionally by the perception that their mother is closer to another child. Second, recollections of favoritism in childhood may be more difficult to ignore despite attempts to maintain harmony, a pattern consistent with
Bedford's (1989) findings regarding favoritism and parent-child relations. This may be because childhood favoritism is more pronounced and visible to all of the siblings because they coreside and interact frequently. Under such circumstances, it is likely that siblings develop a shared perception regarding favoritism, thus reinforcing the individual child's perceptions. In contrast, when mothers favor some children in adulthood—particularly regarding emotional closeness—siblings may not be aware of or have an accurate assessment of such patterns. In other analyses, we have found that adult children's perceptions of their mothers' current favoritism are often inconsistent with the mothers' own reports (
Suitor, Sechrist, Steinhour & Pillemer, 2006). If these processes are occurring, we should not be surprised either that current favoritism predicts only closeness, or that recollections of favoritism from childhood have broad and enduring effects on both closeness and conflict.
It is possible that the differences in the effects of current and recalled favoritism on sibling conflict might also be attributed, in part, to the ways in which we conceptualized and measured favoritism at these two points in the life course. Our measure of favoritism in adulthood focused on perceived emotional closeness; in contrast, our measure of childhood recollections asked siblings to recall favoritism in a more generalized manner, which might elicit memories of preferences regarding both emotional and instrumental resources.
One might question whether current perceptions of favoritism did not predict sibling conflict because both current and recalled favoritism were included in the same models. This does not appear to be the case. First, current perceptions and recollections of favoritism from childhood were correlated weakly (.10), Second, we conducted separate analyses in which we omitted childhood favoritism from the models; these analyses also revealed no association between current perceptions and sibling conflict.
Based on theories of personal and interpersonal development across the life course (
Charles & Carstensen, 2008;
Coats & Blanchard-Fields, 2008;
Lefkowitz & Fingerman, 2003;
Erikson, 1980,
1997), we hypothesized that the effects of both current and recalled favoritism would be greater among younger than older individuals. However, our hypothesis was not supported for either closeness or conflict. These findings are surprising; as we just noted, individuals tend to emphasize positive aspects of their relationship, as well as regulate their emotions more effectively within relationships, as they move across the life course (
Charles & Carstensen, 2008;
Coats & Blanchard-Fields, 2008;
Lang & Carstensen, 2002;
Lefkowitz & Fingerman, 2003). We believe that these findings suggest that mothers' favoritism, particularly in childhood, may have much more intense and lasting consequences on sibling relationship quality than has been demonstrated by previous studies examining only current favoritism. Such a pattern would be consistent with
Bedford's (1992) findings that perceptions of earlier maternal favoritism shaped adult daughters' closeness and affectional solidarity with their mothers.
It is interesting to note that we found no effects of race on the quality of sibling relations. Although the literature on race and family often reports greater intergenerational closeness among Blacks than Whites (
Aquilino, 1997;
1999;
Lawton, Silverstein, & Bengtson, 1994;
Umberson, 1992), this pattern has not been mirrored in studies of siblings. In fact, our nonfindings are consistent with the few other studies that have examined this issue (
Spitze & Trent, 2006;
White & Reidmann, 1992). Thus, it appears that race may play a smaller role in relationships among siblings than between parents and adult children.
Our findings regarding the effects of gender, age, and family size also are congruent with other studies of sibling relations in adulthood. Specifically, sisters tended to report closer relationships than did brothers, as typically found in studies of siblings in adulthood (
Connidis, 1989;
Connidis & Campbell, 1995;
Riggio, 2006;
Spitze & Trent, 2006;
White & Riedmann, 1992). Further, although siblings' age did not affect closeness, it was a strong predictor of conflict, consistent with the preponderance of studies of sibling relations (
Bedford, 1989;
Cicirelli, 1995;
1996;
Stewart et al., 2001) and the broader literature on conflict and age (
Birditt & Fingerman, 2005;
Carstensen, 1987;
Suitor et al., 1990). Finally, similar to other studies of sibling relations in adulthood (
Riggio, 2006), respondents with a greater number of siblings reported greater closeness.
It is worth noting that our findings are very similar to those of
Boll and colleagues' (2005) study of German families. Both our findings and those of Boll and colleagues demonstrate that sibling relations are closest when mothers do not favor any children in the family, suggesting that the effects of favoritism on closeness are similar across Western industrialized societies, despite other cross-cultural differences in family interaction (
Oetzel et al., 2003). The present study expands this line of work by demonstrating the important role of recollections of favoritism. Further, the age range of the adult children in the present study is substantially greater than that of Boll and colleagues' study; in fact, 42% of the siblings in the present study are between 23 and 41 years of age, whereas the youngest sibling in Boll and colleagues' study was 42. Thus, the present findings also show that the effects of maternal favoritism are not restricted to the middle years.
In sum, we believe that the findings we have presented shed new light on the consequences of parental favoritism on adult children's lives. Nevertheless, it is important to note the limitations of the present study. First, as discussed in the Methods section, we used single-item measures of sibling closeness and conflict. Although multiple-item scales are preferable, the findings of the present study give us confidence in these measures. Less reliable measures, including single-item measures, tend to attenuate associations (
Lord & Novick, 1968). However, the patterns of findings in the present study were consistent with expectations. Not only were closeness and conflict predicted by mothers' favoritism, as hypothesized, but age predicted conflict and gender predicted closeness, as expected based upon the literature. In fact, given the fact that single-item measures would be expected to attenuate coefficients, the relationships that we found might have been even stronger had we used multiple-item measures with high reliability.
It is worth noting that respondents were asked about their relationships with siblings in the aggregate rather than asked about each sibling individually. Studies of within-family differences in adulthood have demonstrated that there is considerable variation in the quality of relationships among family members (
Suitor & Pillemer, 2006,
2007). Thus, we believe that it is highly likely that there is variation within families in the quality of sibling relations. It is not clear, however, whether the effects of perceived favoritism would differ depending upon which measure was used. The fact that perceptions of favoritism reduced relationship quality regardless of which sibling was favored suggests that the effects would be similar for both single-dyad and aggregate measures. This is an issue we hope will be pursued in future studies of sibling relations.
A limitation imposed by the cross-sectional nature of our data is the ability to ascertain causal direction. Although we hypothesized that perceptions of favoritism affect sibling relationship quality, we recognize that mothers' favoritism is not necessarily causally prior to sibling relationship quality. Without longitudinal data we cannot rule out this possibility; however, panel studies of young families have shown both that children's behaviors affect parental favoritism (
Tucker, McHale, & Crouter, 2003) and that favoritism produces behavior problems in children (
Richmond, Stocker, & Rienks, 2005). Taken together, these studies suggest that, although adult children's behaviors toward one another may affect parents' favoritism, it is also likely that parental favoritism affects children's behaviors.
Finally, the WFDS data were collected in the Boston metropolitan area. Although Boston has been the site of prominent studies of intergenerational relations (
Pillemer & Finkelhor, 1988;
Rossi & Rossi, 1990), we recognize that such regionality might introduce limitations. Our concern regarding this issue is reduced by a recent investigation using NSFH data that found that the only significant regional differences in intergenerational relations were between Southern and all other families (
Sechrist, Suitor, Henderson, Cline, & Steinhour, 2007). These findings suggest that region plays a relatively small role in family processes in the middle and later years.
Future research on favoritism and sibling relations should address several questions we were not able to explore in the present study. First, it is important to devote greater attention to the consequences of fathers' favoritism. Research indicates that fathers and mothers are almost equally likely to favor some children over others (
Suitor & Pillemer, in press); however, it is not known whether the consequences of favoritism vary by parents' gender. Future research should also examine the patterns and consequences of favoritism in other ethnic groups, such as Hispanics and Asians, who have received scant attention in studies of within-family differences in later life.
Another set of questions worthy of attention involves the circumstances surrounding parents' favoritism. For example, research on families in the younger years has shown that sibling relations are affected less negatively by parental favoritism when offspring believe that such differentiation is acceptable because the favored child is needier (
Kowal & Kramer, 1997;
McHale & Pawletko, 1992). Future studies should attempt to take into consideration whether such conditions lead adult siblings to feel that favoritism is warranted and therefore fair. A related issue is whether offspring's shared perceptions of both the existence and patterns of favoritism shape the way in which sibling relations are affected. This question is theoretically interesting because it brings the issue of transitivity (
Heider, 1958) into the study of adult siblings relations. To examine this question requires detailed information from each child on his or her perceptions of the specific patterns of favoritism in childhood as well as adulthood. Thus, our data do not permit us to examine this issue. We hope that future studies will take many of these questions into consideration.
In summary, the findings we have presented demonstrate that perceived maternal favoritism plays a role in sibling relations in adulthood that is similar to that found in childhood. The findings also suggest that adult children's recollections of their mothers' favoritism in childhood continue to shape their relations with siblings in adulthood, complementing other studies that demonstrate continuity in family processes across the life course (
Bedford, 1992;
Connidis, 1989;
Rossi & Rossi, 1990).
Most important, this study contributes to a consistent picture of patterns of within-family differences across the life course. Previous work has shown that the existence and predictors of within-family differences are remarkably similar across childhood, adolescence, and adulthood (
Suitor et al., 2008). The present study extends this line of research by demonstrating that there is also similarity in the
consequences of within-family favoritism, at least in terms of the effects on adult sibling relationships.