A recent study conducted by the National Institute of Child Health and Human Development (NICHD) sheds more light on this. They examined over 1,000 infants and their mothers at age 6 months and again at 15 months. The mothers were interviewed and the infants were observed at home and, where possible, in day care. The findings showed that those infants with extensive day-care experience did not differ from infants without day care in terms of the distress they exhibited during separations from mother in the Strange Situation.
This suggests that the day-care experience had no immediate effects on attachment. Also, the study did not find any differences in terms of the age of the infants when they first started day care, the amount of day care, or the type of care. However, they did find effects in relation to maternal sensitivity and responsiveness. Infants were less likely to be secure when low maternal sensitivity or responsiveness was combined with poor quality childcare, more than minimal amounts of childcare, or more than one care arrangement.
In other words, a build-up of negative factors did create problems. Egeland and Hiester (1995) found an interesting interaction effect. This study looked at about 70 children, about half of whom entered day care before the age of 1, and the rest remained at home with their mothers. All the children came from impoverished backgrounds. Security of attachment was assessed in the Strange Situation around the age of 1, and then the children were assessed again at the age of 5 and a half years old, in a structured observation session.
Day care appeared to have a negative effect for secure children, but had a positive influence for insecure children. One might be able to explain this in terms of the fact that insecurely attached children needed compensatory education, and therefore benefited from day care, whereas the securely attached children did not require this extra attention. However, later reports on socio-emotional development found no differences between the two groups. These findings again suggest that what appears to mater is not the day-care experience itself, but the conditions under which it may be positively beneficial.