Asking how daycare affects a child's behavior and development is a lot like asking how parenting affects a child's behavior and development. The short answer is, daycare has a variety of measurable effects, many of them positive and some of them negative. And they hinge on the quality of the care, the type of care, and the amount of time spent in it, pretty much as with parenting.
Researchers now know that the nature of daycare arrangements (more than ten hours a week spent in the care of someone other than the mother) has a long reach. The type and quality of care can influence many aspects of development—including memory, language development, school readiness, math and reading achievement, the nature of relationships with parents and teachers, social skills, work habits, and behavioral adjustment—at least through grade school. That's important because in many domains, patterns established by the third grade tend to become highly stable and enduring.
The single best source of information about the effects of childcare is the still-ongoing study begun by the National Institute of Child Health and Human Development in the early 1990s. In 1991, the study enrolled 1,364 children at birth in ten locations around the U.S. and carefully observed and monitored them periodically in whatever care situations their family chose—center-based daycare, daycare in a home, at-home care (including maternal care and nanny care), grandparent care, father care. The study has continued to monitor them through grade school and beyond.
Recently, a new wave of results was released and made news because they confirmed and bolstered the validity of an earlier finding that daycare is associated with some negative effects on child behavior. The study found that the more time a child spent in center-based daycare before kindergarten the more likely their sixth grade teacher was to report that the child "gets in many fights," is "disobedient at school," and "argues a lot."
The authors stress that their study is correlational, and thus it cannot say for sure what is the cause of the aggression and disobedience. They also emphasize that the size of the effect is small. However, because the quality of childcare in the community varies much more than it does in the study, it could actually be understating the effect of center-based daycare on problem behavior. But even a modest effect on behavior would have a big impact in classrooms around the country. The researchers emphasize that many millions of children are in daycare, and for 60 percent of them, the care-giving is neither sensitive nor responsive to their needs.
The study authors suggest that the correlation between center care and problem behaviors could be due to the fact that center-based child-care providers often lack the training, as well as the time, to address behavior problems. For example, center-based child-care providers may not be able to provide sufficient adult attention or guidance to address problems that may emerge when groups of young children are together, such as how to resolve conflicts over toys or activities.
The latest wave of results also demonstrated that regardless of the amount of time they spent in childcare or the type of care, those children who received higher quality child care in the early years also had better vocabularies in the fifth grade than kids who received lower-quality care. Early exposure to adult language aided children's language development. High-quality care is defined in the study as "sensitive and responsive," reflecting the caregiver-child interaction and stimulation, and it was readily detectable by trained observers who made multiple visits to each site.
How parents choose to raise their children is among the most important decisions they make. People have a great emotional stake in believing that their childcare decision is the right one. Most parents want "the best" for their children.
It's important for parents, educators and lawmakers to have a complete picture of the effects of daycare on children. Among the varied findings to date:
Memory: Children who spent more time in center-based care displayed an early advantage. They tended to score higher on standardized tests of short-term memory. This effect emerged even before starting school and is maintained during the primary grades.
Cognitive development: Sensitive and responsive care-giving leads to academic achievement throughout the primary grades, as measured by tests of math, reading, and such cognitive processes as memory for sentences.
Social skills: Early positive effects of high-quality care on cooperation, assertion, responsibility, and self control seemed to disappear at later ages—although the researchers point out that long-term positive effects on social development may well reappear at a later age because development is dynamic.
Behavior problems: Even high-quality care did not reduce the number of behavior problems among those in childcare.
Conflictual relationships: More time spent in center-based child-care led to reports of more conflict—with parents and teacher.
Work habits: The greater the amount of time children spent in childcare in kindergarten, the more their teachers later reported that they do not work independently, did not use their time wisely, and did not complete their work promptly in grade school.
Social-emotional functioning: How skilled children are with peers and how well they solve problems with them was negatively impacted by many hours in daycare.