Individual Differences

Theories and research on individual differences are concerned with exploring the underlying psychological determinants (e.g. temperament, intelligence, attitudes, psychopathology etc.) that explain observable differences between individuals (Chamorro-Premuzic, 2016). Individual differences can act as vulnerabilities affecting an individual’s appraisal and coping strategies in respect to social situations. For these reasons, exploring the influence of individual differences may be particularly important towards understanding the development of sibling aggression.

Social-Cognitive Abilities

Children with poor social-cognitive abilities including perspective taking, theory of mind or the ability to understand emotion (i.e. behavioural or social cues and facial expressions) have for instance been frequently associated with poor social competence skills and difficulties regulating emotional responses in social environments (Bengtsson & Arvidsson, 2011; Eisenberg, Fabes, Bernzweig, Karbon, Poulin, & Hanish, 1993; Trentacosta & Fine, 2010). There is also evidence suggesting that children who are high in aggression have difficulties with the interpretation and perception of social cues (Hall, 2006; Bowen & Dixon, 2010). Moreover, in the peer literature, low IQ in childhood has been reported as a risk factor for peer bullying (Farrington & Baldry, 2010). Examining children’s social-cognitive abilities may

hence be a novel route towards better understanding the development of sibling bullying.

Behavioural Problems

Furthermore, some children may exhibit early signs of behavioural problems that could be indicative of a life-course persistent antisocial behaviour trajectory (Moffitt & Caspi, 2001), which is implicated with impairments in social functioning (Bongers, Koot, van der Ende, & Verhulst, 2008). Children who have difficult temperaments, display externalizing (e.g. conduct problems or hyperactivity) or peer problems have for instance been identified as more likely to engage in aggressive behaviour in childhood and adolescence (Kkkinos & Panayiotou, 2004; Moffitt & Caspi, 2001; Olson et al., 2011; Ribeaud & Eisner, 2010; Tremblay et al., 2004). Antisocial behaviour and externalizing problems in childhood have further been identified as strong predictors of peer bullying (Cook et al., 2010; Farrington & Baldry, 2010), allowing for similar predictions to be made about sibling bullying.

Self-Concept

Constructs relating to one’s self-concept may also be important factors that can predict sibling aggression. In the peer bullying literature, children who hold negative self- related cognitions pertaining to attitudes and beliefs about themselves, have been found to become victimised more often by their peers compared to children with more positive self-related cognitions (Cook et al., 2010; Kokkinos & Panayiotou, 2004; Salmivalli et al., 1999). Furthermore, adolescents with low self-esteem and external locus of control have been found to display higher levels of aggression (Wallace, Barry, Zeigler-Hill, & Green, 2012). Similar associations may therefore be found for sibling bullying.

Psychopathology

Problems with regulating one’s emotions and self-control have also been linked with aggression in childhood and adolescence (Ribeaud & Eisner, 2010; Olson, Lopez- Duran, Lunkenheimer, Chang, & Sameroff, 2011). Particularly those with some form of psychopathology are reported to have elevated problems in emotion-regulation, emotion-reactivity as well as self-regulation (Gross & Jazaieri, 2014). Scholars have

of engaging in emotionally charged acts of aggression and violence (Arseneault, Moffitt, Caspi, Taylor, & Silva, 2000; Cook, Williams, Guerra, Kim, & Sadek, 2010). Internalizing problems have additionally been identified as a probable predictor of peer bullying (Cook et al., 2010).

Sex

Finally, gender differences in particular are identified as strong and consistent predictors of aggression, with males typically engaging in more aggression (Archer, 2004; Card, Stucky, Sawalani, & Little, 2008).

Predictions

1. A child that is unable to interpret social cues (e.g. facial emotion recognition) effectively may be more likely to provoke conflicting interactions with their brothers or sisters (more sibling bullying victimisation and perpetration). 2. Children with difficult temperament, more regulatory problems (i.e. crying,

feeding, sleeping), higher levels of externalizing problems and antisocial behaviour experiences will more likely be involved in sibling bullying (victimisation and perpetration).

3. Negative self-related cognitions (e.g. self-esteem or locus of control) may predict sibling bullying (victimisation and perpetration).

4. Children with psychopathology (e.g. psychiatric diagnosis, internalizing problems, IQ) will more often be involved in sibling bullying (victimisation and perpetration).

5. Males will more often bully their siblings compared to females. 2.1.7 Summary

Table 2.1 provides a summary and overview of all theories introduced and discussed above.

Table 2.1

Summary of Key Theoretical Perspectives Explaining the Development of Sibling Aggression Theoretical

Perspective Theoretical Framework Predictions about Sibling Bullying Empirical Evidence

Evolutionary

Siblings are natural born competitors for limited parental resources.

Asymmetries in social groups lead to social dominance and resource-directed agonistic behaviour used for resource acquisition.

Structural family characteristics and household composition predict sibling bullying (perpetration and

victimisation).

Berkel et al., 2018; Bowes et al., 2014; Eriksen & Jensen, 2006, 2009; Hoffman et al., 2005; Menesini et al., 2010; Straus et al., 2006; Tucker et al., 2013; Tucker et al., 2014)

Attachment

Primary caregiver-child relationship fosters internal working model of interpersonal relationships (i.e. shapes individual’s expectations,

understanding, emotions and behaviours surrounding social interactions).

Supportive and warm parenting may protect against sibling bullying (victimisation and perpetration). Inconsistent and unpredictable

parenting may predict sibling bullying (victimisation and perpetration).

Updegraff et al., 2005; Miller et al., 2012; Tippett & Wolke, 2015; Tucker et al., 204

Table 2.1

Summary of Key Theoretical Perspectives Explaining the Development of Sibling Aggression Theoretical

Perspective Theoretical Framework Predictions about Sibling Bullying Empirical Evidence

Family System Theory

Families are interdependent social systems in which individuals interact and mutually influence one another in a bidirectional fashion (parent–child; child–parent; parent–parent; child– child).

This is a heuristic model; no specific predictions can be made. Stresses the importance of including multiple family sub-systems (e.g. parent- parent; child-parent; child-sibling) when exploring the precursors of sibling bullying.

–

Social Learning

Behaviour is learned through mechanisms of observation and reinforcement. Behaviour resulting in desired outcomes will be modelled in future contexts, whereas behaviour resulting in undesired outcomes will be avoided.

Witnessing domestic violence or experiencing abuse by parents/peers may predict sibling bullying

(perpetration).

Berkel et al., 2018; Bowes et al., 2014; Button & Gealt, 2010; Eriksen & Jensen, 2006, 2009; Hoffman et al., 2005; Menesini et al., 2010; Radford et al., 2013; Straus et al., 2006; Tippett & Wolke, 2015; Tucker et al., 2013; Tucker et al., 2014; Updegraff et al., 2005)

Table 2.1

Summary of Key Theoretical Perspectives Explaining the Development of Sibling Aggression Theoretical

Perspective Theoretical Framework Predictions about Sibling Bullying Empirical Evidence

Coercion

Parental failure to effectively discipline/control coercive family exchanges (i.e. aversive behaviours) permits sibling conflict. When left unchecked, sibling conflict will increase in frequency/amplitude allowing for escalating aggression between siblings. This may place a child at risk for other poor social relationships.

Ineffective parenting (e.g.

inconsistent or shouting/hitting) that permits negative child behaviour (e.g. early sibling aggression) may predict sibling bullying (victimisation and perpetration).

Berkel et al., 2018; Bowes et al., 2014; Button & Gealt, 2010; Eriksen & Jensen, 2006, 2009; Hoffman et al., 2005; Menesini et al., 2010; Radford et al., 2013; Straus et al., 2006; Tippett & Wolke, 2015; Tucker et al., 2013; Tucker et al., 2014; Updegraff et al., 2005)

Individual Differences

Child individual differences place children on different developmental trajectories.

Child individual differences (e.g. internalizing/externalizing problems) may differentially predict sibling bullying (victimisation or

perpetration).

Brody et al., 1994; Bowes et al., 2014; Menesini et al., 2010; Philipps et al., 2016; Rose et al., 2016; Tippett & Wolke, 2015; Toseeb et al., 2018; Song et al., 2016