In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.

Article: It has been argued that an infant under three who is cared for outside the home may suffer because of the separation from his parents.The British psychoanalyst John Bowlby believes that separation from the parents during the sensitive "attachment" period from birth to three may scar a child's personality and incline to emotional problems in later life.Some people have drawn the conclusion from Bowlby's work that children should not be sent to day care before the age of three, and many people do believe this.But there are also arguments against such a strong conclusion. Firstly, anthropologists point out that the hidden love between children and parents found in modem societies does not usually exist in traditional societies.For example, we saw earlier that among the Ngonis the father and mother of a child did not raise their infant alone.But traditional societies are so different from modern societies that comparisons based on just one factor are hard to understand. Secondly, common sense tells us that day care would not be so widespread today if parents and caretakers found that children had problems with it.But Bowlby's analysis raises the possibility that early day care has delayed effects.The possibility that such care might lead to more mental illness or crime 15 or 20 years later can only be noticed by the use of statistics.Statistical studies of this kind have not yet been carried out, and even if they were, the results would be certain to be complicated and controversial. Thirdly, in the last decade, there have been a number of careful American studies of children in day care, and they have reported that day care had a neutral of slightly positive effect on children's development.But tests that have had to be used to measure this development are not widely enough accepted to settle the issue.
Answer: negative effect of infant school
This passage is mainly talking about _ .