magazine issue 10 2014 / Issue 23

The influential child: It is not all up to the parents

• written by Reut Avinun
• edited by Reine van der Wal

To what extent does the child's genotype affect parenting?

A child-based twin design can be used to assess whether monozygotic/identical (MZ) twins are treated more similarly by their parents than dizygotic/non-identical (DZ) twins. If MZs are in fact treated more similarly, it indicates that genetics are at play. It indicates that the genes that make MZs alike also make their parents treat them similarly (Neiderhiser et al., 2004). Various child-based twin studies have shown that children affect the parenting they experience (Avinun & Knafo, 2014). Additionally, as children grow older their evocative effect on parents grows stronger (Elkins, McGue, & Iacono, 1997). This makes sense, because as children grow older they gain independence and show their personality more freely, which in turn can lead to a larger effect on parenting.

How does the child's genotype affect parenting?

Studies have also examined specific child behaviors that may affect parenting. For instance, the same genetic factors that predispose 5-month-old infants to be fussy, also lead them to elicit more negative behaviors from their mothers (Boivin et al., 2005). In other words, mothers of difficult and fussy infants are more likely to show anger toward them, than mothers whose infants are easier to handle. Another study focused on mother-reported physical punishment and maltreatment in 5-year-old twins living in England and Wales (Jaffee et al., 2004). Results showed that the same genetic factors that predispose children to antisocial behavior also predispose them to experience higher levels of physical punishment from their parents. Maltreatment, however, did not depend on the child's behavior. Thus aggressive and oppositional behavior of children evoked more frequent physical punishment. Notably, these findings do not legitimize physical punishment. Rather, they stress the importance of fully understanding the factors that underlie parenting, to enable conscious parental responses that will break negative child-parent reaction cycles.

Another way to examine evocative rGE is to study adoptive families. Adoptions enable us to discern the difference between heritable (biological parents) and environmental (e.g., adoptive parents) effects on the adoptee's behavior. For example, Ge et al. (1996) showed that adoptive parents' parental behavior was associated with the adoptees’ biological parents' psychiatric status. This association was mediated by the adoptees’ behavior. Specifically, adoptees born to parents with psychopathologies were more hostile and antisocial and as a reaction their adoptive parents used harsh discipline more, and were less nurturing and involved (see also O'Connor, Deater-Deckard, Fulker, Rutter, & Plomin, 1998). One interpretation of these findings is that having genes of parents with psychopathologies affects the adoptees' behavior negatively, which in turn affects adoptive parents' parenting.

The effect of the child's characteristics was also shown in a study that examined the home environment of 24-month-old toddlers (Saudino & Plomin, 1997). Observational methods and questionnaires were used in order to estimate the emotional and verbal responsivity of the mother, her involvement, avoidance of restriction, organization of the child's environment, provision of appropriate toys and stimulation. The results demonstrated that the genetic factors that influence the toddlers' attention characteristics, such as: attention span, persistence and goal directedness, also influence maternal involvement (child's genes  child's attention characteristics  maternal involvement and responsivity). Hence, parents appear to respond to the first buds of their toddler's personality. Interestingly, the child's attention characteristics did not seem to affect the home environment 12 months before, when children were one year old. Parents may need time in order to develop a clearer picture of their infant's attentional attributes and adjust the environment accordingly.

Are all parents similarly affected by children's behaviors?

Just like different children evoke different responses from parents, different parents react differently to the same child behavior. Indeed, research indicates that the interplay between children's and parents' characteristics can produce unique contexts for development. Infant's irritability (assessed when infants were 10 days old) was associated with postnatal depression at two-months in high-risk mothers (Murray, Stanley, Hooper, King, & Fiori-Cowley, 1996). Mothers were rated as being at high-risk for postnatal depression based on a predictive index that included questions regarding the experience of pregnancy, previous mood disorder and the quality of close relationships. When these vulnerable mothers had irritable infants they were more likely to fall into depression.

Furthermore, having an infant with poor motor functioning (i.e., poor quality of movement and activity level rated as either hypo- or hyper-aroused) increases the likelihood of postnatal depression in both low- and high-risk mothers. One suggested explanation for this pervasive effect was that these infants are less responsive to parental attention, which limits opportunities for satisfying and rewarding parent-infant interactions. In contrast with poor motor functioning, fussing and crying, although frustrating, may still be seen as attempts of the infant to communicate various needs, and consequently be treated with more understanding and patience by mothers who have the emotional resources to do so. The study demonstrates how the effect of the child on the parent can be conditional. Irritable infants require more attention, and the question is whether their caregivers have the resources to handle the additional challenge they present