Center-based child care: Long hours do not cause aggression and disobedience

Spending many hours in centre-based child care does not lead to more aggression and disobedience in children, according to a new study using data from the Norwegian Mother and Child Cohort Study (MoBa).

Data from 72,000 mothers and their children, including siblings, were obtained from MoBa. Using questionnaires, mothers were asked about aggression and obedience at both 18 and 36 months and the amount of time their children spent in child care. In addition to comparing children from different families, the researchers compared siblings who had different amounts of child care.

"These are exciting findings because they contradict research from the USA. There are two likely reasons for this; one is the nature of Norwegian centre-based child care, the other concerns research methods" says primary author Henrik Zachrisson, researcher at the Norwegian Institute of Public Health and the Norwegian Centre for Child Behavioural Development.

"Norwegian families have easy access to good quality centre-based child care. Each carer is responsible for fewer children than in most other countries. We also offer paid parental leave which means that children usually begin child care at one year old or later, in contrast to the USA where children may start when they are just a few months old. So the Norwegian work-family policy could be part of the explanation," explains Zachrisson.

The researchers found no increase in problematic behaviour among the siblings who spent more hours in child care. They also found that when children were followed over time, increases in the amount of child care were not linked to deterioration in behaviour. This is in stark contrast to findings from the USA that indicate that longer hours in child care are associated with higher levels of aggression and disobedience compared to children who have had little or no child care.

"Using data from MoBa gives us unique possibilities. For example we were able to compare siblings who spent different hours in child care. This means that we can effectively account for many family factors that influence both how long children spend in child care and at the same time have an effect on their behaviour. We are the first to study this association using these methods. It is important to note that when we used the same methods as earlier studies, we found similar results to other researchers, although the association was not as strong. MoBa gives us the possibility to dig deeper and achieve more accurate results" concludes Zachrisson.

Co-authors of the study are Eric Dearing from Boston College, Claudio O. Toppelberg from Harvard Medical School and Ratib Lekhal from the Norwegian Institute of Public Health.

Zachrisson HD, Dearing E, Lekhal R, Toppelberg CO.Little Evidence that Time in Child Care Causes Externalizing Problems during Early Childhood in Norway Child Dev. 2013 Jan 11. doi: 10.1111/cdev.12040. [Epub ahead of print]