Families in motion : changes with the arrival of a second child

The aim of the present dissertation was to examine the causes and consequences of the arrival of the second child—from both family systems and evolutionary perspectives. Chapter 2 compared parent–child interaction in dyadic and triadic settings and examined how parental warmth and investment change as a function of the other parent’s presence. The sample consisted of 87 two-parent Dutch families raising firstborn preschoolers. In line with the evolutionary theory, mothers’ warmth and investment did not change as a function of fathers’ presence, but fathers withdrew care in the presence of mothers. However, when mothers were away, fathers raised their level of care to that of mothers compensating for maternal absence. Chapter 3 investigated whether the length of interbirth-intervals in a middle class of U.S. American population could be explained by paternal and alloparental support, the firstborn children’s gender and temperament. Two hundred forty-one families in which mothers were expecting their second child participated. In families where fathers showed more support parents waited shorter with having a second child. Furthermore, alloparental support seemed to shorten birth spacing between the two children for families with a firstborn son. In addition, parents with a firstborn daughter or a difficult child waited longer to have a second baby. Chapter 4, 5 and 6 described three empirical studies examining 87 Dutch families participating in the present dissertation project. Chapter 4 investigated how having a second child influenced the stability of coparenting and whether coparenting was affected by child temperament. Parents reported no change in their coparenting relationship with regard to child 1, however, their observed coparental cooperation increased over time. Parents reported similar coparenting across their two children, with mothers reporting somewhat better coparenting relationship with regard to child 2. Moreover, child 1’s temperament had no influence on coparenting, whereas the difficult temperament of child 2 decreased coparenting stability with child 1 and lowered the predictability of coparenting with child 2. Chapter 5 examined childhood jealousy across multiple contexts. Children were challenged in several jealousy-evoking situations using social and non-social objects as their rivals for parental attention during family play situations. We found that social forms of exclusion (e.g., introducing a doll) were more likely to evoke jealousy in toddlers than losing attention to non-social objects (e.g., anagram task). Furthermore, children consistently showed more jealous behavior towards mothers than fathers. Chapter 6 investigated the issue of predicting early sibling relationship quality based on the characteristics of the marital and the parent–child subsystem before the birth of the second child. When parents reported high marital quality their firstborn showed less jealousy towards the father when he attended to the younger sibling. Furthermore, firstborns with warm parents were more likely to accept and less likely to reject their 1-year old siblings. We found evidence for short-term stability of early sibling jealousy as measured just before and after the birth of the second child and discontinuity in firstborns’ jealousy reactions from toddlerhood to preschool.