Concerns regarding the possibility of mental health risks associated with group day-care were first raised half a century ago (Bowlby, 1951; WHO Expert Committee on Mental Health, 1951). However, over the years, there has been a highly controversial debate regarding the effects of day-care and the issue is still far from resolved now (Borge, Rutter, Cote & Tremblay, 2004; Belsky, 2001).
Firstly, before moving on to reviewing the empirical evidence for various theories regarding the day-care effects, it is important to acknowledge social selection and social causation effects (Borge et al., 2004). Social selection occurs as day-care is not randomly allocated in the general population (Clarke-Stewart & Allhusen, 2002). Families' choice of which day-care to use, if any at all, would be influenced by whether both parents work outside the home, attitudes to day-care, availability of day-care provision, and family's ability to pay if free care is unavailable. These factors vary across different nations and regions so social selection might not occur in the same way across populations (Borge, Hartman & StrÃÂ¸m, 1994).
The more recent studies have paid more attention to selection effects and statistically controlled for them, compared to earlier research in this field.
Social causation refers to the possible differential childcare effects in certain subgroups of a population. Interactions between childcare features and child and family attributes need to be considered to correctly identify conditions in which day-care enhances and/or impairs children's socioemotional development (McCartney & Galanoupoulos, 1988). Three kinds of interactions have been discerned from previous research.
According to the compensatory or protective conceptualisation, quality day-care experience could serve to attenuate risk caused by child (e.g. temperament) or family attributes (e.g. poor). Day-care would protect high-risk children by decreasing exposure to home conditions. This was in accord with empirical findings showing that high-quality day-care settings protected...