It’s the fact of the debate, rather than the fact of the day care, that the research team I described above, authors of a more recent study, suggest is primarily responsible for any association between unruly behavior and time spent in day care. In Norway, where day care is subsidized, of a reasonably consistent quality, and an expected part of childhood (in 2009, 79 percent of all 1- to 2-year-olds, and 97 percent of all 3- to 5-year-olds attended publicly subsidized center care there), researchers found little evidence that more time in day care could be associated with “externalizing problems” like defiance and restlessness, in 3-year-olds (a result they hope to confirm in older children).

In other words, when all the energy that goes into debating the merits of day care is put, instead, into ensuring that day care is of a high quality and available to everyone, then any association between time spent in that care and poor behavior essentially disappears. “Whereas child care in U.S. policy is generally treated as an unintended or unfortunate consequence of workforce participation among women,” the researchers wrote, “child care in the Norwegian corporatist economy is part of a broader family policy to promote maternal workforce participation and employment rights … as well as universal access to high-quality environments for learning and development beginning in the second year of life.”

That’s consistent with the U.S. research as well. In 2007, Slate’s Emily Bazelon contacted the author of that much-publicized earlier study, and asked her to examine the quality of care received by the children who spent more time in day care, and who had a higher-than-average incidence of bad behavior. “The kids with more reported behavior problems in elementary school were the ones who spent three or four years in day care and whose care was, on average, of lower quality.”