Lean In: Women, Work, and the Will to Lead

by Sheryl Sandberg

In 1991, the Early Child Care Research Network, under the auspices of the National Institute of Child Health and Human Development, initiated the most ambitious and comprehensive study to date on the relationship between child care and child development, and in particular on the effect of exclusive maternal care versus child care. The Research Network, which comprised more than thirty child development experts from leading universities across the country, spent eighteen months designing the study. They tracked more than one thousand children over the course of fifteen years, repeatedly assessing the children’s cognitive skills, language abilities, and social behaviors. Dozens of papers have been published about what they found.23 In 2006, the researchers released a report summarizing their findings, which concluded that “children who were cared for exclusively by their mothers did not develop differently than those who were also cared for by others.”24 They found no gap in cognitive skills, language competence, social competence, ability to build and maintain relationships, or in the quality of the mother-child bond.25 Parental behavioral factors—including fathers who are responsive and positive, mothers who favor “self-directed child behavior,” and parents with emotional intimacy in their marriages—influence a child’s development two to three times more than any form of child care.26 One of the findings is worth reading slowly, maybe even twice: “Exclusive maternal care w...