Scientists have known about the link between attachment and friendship quality, but they haven't understood the reasons it exists.
The study included 1,071 children from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. Researchers assessed mother-child attachment at age three. They also assessed how openly mothers and children acknowledged and communicated about their emotions when the child was four and a half.
"In a secure, emotionally open mother-child relationship, children develop a more positive, less biased understanding of others, which then promotes more positive friendships during the early school years," said Nancy McElwain, a U of I assistant professor of human and community development and lead author of the study. "We found several ways in which the early mother-child relationship may affect later friendship quality."
She noted that a number of measures were used.
At four and a half years and again in first grade, children were assessed for what the researchers called a hostile attribution bias. In this type of assessment, the child was given a series of hypothetical vignettes in which a peer did something negative to the child, although it wasn't clear if the peer had meant to hurt or antagonize the child.
For example, an interviewer might say, "John throws a ball and it hits you in the back." The child was then asked why his peer had acted in that way. If a child interpreted the peer's behavior as intentional (for example, "He meant to hit me in the back"), it indicated a hostile attribution bias.
Child language ability was also evaluated at four a half years and again in first grade.
Finally, mothers and teachers were asked to report on the child's general peer competence in first grade and the quality of the child's relationship with his or her closest friend in third grade.
Several pathways led from close early mother-child attachment to later friendship quality. In one pathway, children who were securely attached at age three showed more open emotional communication with mothers and better language ability at four and a half, she said.
"Open emotional communication in turn predicted fewer hostile attributions at first grade, which predicted greater teacher-reported friendship quality at third grade," she said.
"This finding suggests that the way children interpret other people's behavior may begin to develop in the context of early relationships in the family, and these interpretations may be important for a child's ability to get along with friends later on," she said.
In another pathway, open emotional communication and language ability at age four and a half was related to mother- and teacher-reported friendship quality via the child's general peer competence in first grade.
"When kids feel comfortable talking about their emotions, especially their negative emotions, it increases their social competence with classmates and leads to closer friendships," she said.
"The preschool years are an interesting period to study because the child's rapidly growing language skills allow parents and children to share in ways they haven't been able to before," she noted.
According to McElwain, the relationship between mother-child attachment and children's other close relationships may be an especially important one.
"A child's early attachment relationships are close and emotionally intense. For that reason, those relationships may be important in guiding children's thinking about and functioning in other close relationships," she said.
Co-authors of the study are Cathryn Booth LaForce of the University of Washington, Jennifer E. Lansford of Duke University, and Xiaoying Wu and W. Justin Dyer of the University of Illinois.