Sibling dyads who are closer in age have been identified as an at-risk group for negative sibling interactions (Aguilar, O’Brien, August, Auon, & Hektner, 2001; Buhrmester & Furman, 1990; Felson & Russo, 1988; Minnett, Vandell, & Santrock, 1983; Tanskanen et al., 2017) and victimisation by siblings (Tucker, Finkelhor, Shattuck & Turner, 2013a). One reason for this may be that siblings who have less of an age difference might engage in more conflict because the power structure between the children is less clear (Hoffman & Edwards, 2004). However, there has been evidence of the contrary, with studies reporting no effects of age difference on sibling relationship quality (Recchia & Howe, 2009) or sibling violence (Hoffman, Kiecolt, & Edwards, 2005).
Birth Order
Findings on birth order effects (first born vs. later born) have been mixed in the sibling aggression literature. Some studies have found that later-born children report poorer sibling relationships (Recchia & Howe, 2009) and more sibling aggression (Hoffman et al., 2005; Martin & Ross). Similar findings have been reported using longitudinal data, with more frequent sibling bullying victimisation reported by children with an older sibling (Bowes et al., 2014). Similarly, Bowes et al., 2014 found that first-born children were more often the perpetrators of sibling bullying. However, there is also contradictory evidence suggesting that being the older or first-born child was
associated with more sibling victimisation (van Berkel et al., 2018; Tippett & Wolke, 2015; Tucker et al., 2014a) and others who report no birth order effects (Updegraff, Thayer, Whitemn, Denning, & McHale, 2005).
Dyadic Constellation
Effects for gender composition have equally been mixed. While some studies report more sibling aggression in same-sex sibling pairs (Minnett et al., 1983; Tucker et al., 2013a), others have found that mixed-sex pairs report higher levels of sibling aggression; with older brother-younger sister pairs at the highest risk (Aguilar et al., 2001; Hoffman & Edwards, 2004). The mode of aggression may be one possible explanation for the mixed evidence of gender effects. Male siblings (particularly older males) have for instance been reported to be more physically aggressive, whereas female siblings (particularly older females) were found to be more relationally aggressive (Ostrov, Crick, & Stauffacher, 2006).
Number of Children
Households with more children have been associated with more sibling rivalry (Stocker, Lanthier, & Furman,1997). Similar findings are also reported for sibling aggression. Larger households with more children have been linked to more sibling bullying victimisation (van Berkel et al., 2018; Bowes et al., 2014; Tippett & Wolke, 2015; Toseeb et al., 2018) and perpetration (Tippett & Wolke, 2015; Toseeb et al., 2018). While the majority of findings do find larger households with more children predictive of sibling bullying; there have also been some contradictory findings showing no effect for the number of children and a link to sibling violence (Hardy, 2001; Relva, Fernandos, & Mota, 2013).
Socioeconomic Status
Evidence for socioeconomic status (SES), a proxy of resources in the family, is mixed. In respect to sibling victimisation, some studies show an association with high socioeconomic status (van Berkel et al., 2018), others report more poverty or financial stress (Tippett & Wolke, 2015), yet others show no relationship (Toseeb et al., 2018). In respect to sibling perpetration, some studies have found lower levels of socioeconomic status to be associated with less sibling bullying perpetration (Toeseeb
(Eriksen & Jensen, 2009). Interestingly, children raised in families where mothers have achieved higher educational qualification are reported to have higher levels of physical violence directed at siblings (Eriksen & Jensen, 2009; Tippett & Wolke, 2015) and are also more likely to become victimised (Tucker et al., 2013a; Tucker, Finkelhor, Turner, & Shattuck, 2014b), perhaps because there is more competition for material goods. Other studies report that lower social class is associated with sibling bullying victimisation (Bowes et al., 2014).
Marital Status
Most studies on marital status report that children growing up in single-parent households are no more likely to be involved in sibling bullying victimisation (van Berkel et al., 2018; Hardy, 2001; Tucker et al., 2013a) or perpetration (Toseeb et al., 2018) compared to those growing up in two-parent households. There is also some evidence suggesting the contrary. Children growing up in single-parent families have for example been found to report the highest levels of sibling negativity (Deater- Deckard & Dunn, 2002) and engage in more sibling violence when growing up in step-families (Hofmann et al., 2005).
Summary and Limitations
Table 2.2. provides an overview and summary of the empirical evidence that links structural and family characteristics to sibling aggression. While there is mixed evidence across all selected factors, the literature would largely suggest that sibling bullying occurs more frequently in families with more children. Particularly first-born children or older males are found to act as perpetrators compared to later-born and younger children who tend to become victimised more often. The above-mentioned studies support an evolutionary framework proposing that factors associated with the limitation of resources and heightened competition (e.g. larger households with older or first-born children) should be predictive of sibling aggression.
There are also a few limitations with the current studies on structural family characteristics.
1. Most studies are cross-sectional; with only two prospective studies (Bowes et al., 2014; Toseeb et al., 2018). More longitudinal studies are needed.
2. All current studies have only explored the crude association between individual structural family characteristics and sibling aggression/bullying; without controlling for each other or other potential precursors (e.g. child characteristics). Systematic, well-controlled studies are needed.
3. There is still mixed evidence across most structural family characteristics identified above. More work replicating current findings is needed.
Table 2.2
Summary of Empirical Evidence for Association between Structural and Family Characteristics and Sibling Aggression
Construct Direction Strength of
Association Empirical Evidence
Age spacing Smaller age gap ↑ Sibling aggression
Consistent; some mixed
Aguilar et al., 2001; Hoffman, 2005; Felson & Russo, 1988; Minnett et al., 1983; Recchia & Howe, 2009; Tanskanen et al., 2015; Tucker et al., 2013
Birth order (first vs later) First-Born ↑ Perpetration; Later- Born ↑ Victimization Mixed
Bowes et al., 2014; Berkel et al., 2018; Menesini et al., 2010; Recchia & Howe, 2009; Tippett & Wolke, 2015; Wolke & Skew, 2011
Dyadic constellation (older vs younger) Older children ↑ Perpetration; Younger children ↑ Victimization Consistent; some mixed
Aguilar et al., 2001; Hoffman & Edwards, 2004; Ostrov et al., 2006; Minnett et al., 1983; Tucker et al., 2013
Number of children More children ↑ Sibling
aggression Fairly Consistent
Berkel et al., 2018; Bowes et al., 2014; Hardy, 2001; Tippett & Wolke, 2015; Toseeb et al., 2018
Socioeconomic status Mixed Mixed
Berkel et al., Bowes et al., 2018; Eriksen & Jensen, 2009; 2018; Tippett & Wolke, 2015; Toseeb et al., 2018
Marital status No association Consistent Berkel et al., 2018; Hardy, 2001; Hofmann et al., 2005; Toseeb et al., 2018
2.2.2 Parent and Parenting Characteristics