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Title: Explaining the influence of younger siblings on firstborns' understanding of minds in middle childhood : a longitudinal investigation of the mother-firstborn relationship
Author: Paine, Amy
ISNI:       0000 0004 6425 5969
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2017
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This thesis focuses on the influence of younger siblings on firstborns’ understanding of minds in middle childhood. This topic was investigated in the context of the Cardiff Child Development Study (CCDS): a prospective longitudinal study of firstborn children and their families living in Wales, UK. As reported in Chapter 3, presence of a younger sibling resulted in an advantage on a second-order false belief task at 7 years of age. However, this advantage was only true for firstborns who experienced the birth of a sibling after their second birthday. It was hypothesised that the positive contribution of a younger sibling is mediated by changes to features of mother-firstborn conversation in dyadic interactions. To test this hypothesis, in Chapter 4 I described an expanded internal state language coding scheme for analysing mothers’ speech at 6 months, 21 months and 7 years. Mothers’ references to their 7-year-olds’ cognitive states positively predicted understanding of second- order false belief. As reported in Chapter 5, mothers who had a second child referred to cognitive states more than those with one child in middle childhood. Mothers’ variety of references to cognitive states partially mediated the association between presence of a sibling and firstborns’ understanding of second-order false belief. In Chapter 6, I investigated the families who experienced the birth of an early arrival younger sibling. Early arrival siblings were predicted by mothers’ symptoms of conduct disorder. Mothers who had an early arrival sibling present by 21 months referred to cognitive states less than mothers who did not. The findings in this thesis contribute to knowledge about the influence of younger siblings on the child’s development of theory of mind. The findings demonstrate the importance of examining how the arrival, and timing of arrival, of a younger sibling affects the dynamics of children’s other close relationships that influence children’s developing understanding of minds.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: BF Psychology