The health of a human society depends on maintaining the flow of information. If the flow of information is disrupted the result is often violence. It can even be war.
Of particular concern is the flow in information from the adults to the young. We often refer to that process as education. I think the educational system does more to interfere with this process than to facilitate it.
To become a full member of the society, an infant must learn to talk. It's easy to think that they just lean by watching and listening, but what really happens is that they develop a simple language, which their mother learns. Other people will be able to understand only a small fraction of what an infant says compared to what a mother can understand. As the infant grows, her language comes to be more and more like the language of her adult world, but in its early stages only a mother can tell the difference between many utterances and babbling.
The general everyday comfort of an infant is dependant on communication with those who are taking care of her. So receiving care from someone who does not understand her beginning language is painful, no matter how well intentioned the care, and there are many good reasons to believe that no one is as interested in the welfare of a child as her mother.
So a child who is put in a day care center is put back into a situation she experienced when she was younger and was less skilled at communication. Her caregiver has suddenly ceased to understand her. Therefore, she is likely to revert to behavior from an earlier age, which puts strain on her relationship with the caregiver.
Also, a child has a very limited capacity to process information. Faced with day care, she is forced to develop and understand yet another language to communicate with the day care provider, so she becomes less proficient at communicating with her mother, and the mother spends less time communicating with her, so the mother's understanding also suffers, and the flow of useful information into the child's brain is impeded.
We are not talking book learning here, but something much more fundamental and important, the formation of a stable and well-adjusted personality. The better the communication channel the child has with the adult world, the more rapidly and completely she will be able to understand and adjust to that world.
Far from facilitating the flow of information into an infant's mind, the program we commonly refer to as head start inhibits it. Learning the ABC's requires a trivial amount of time and effort compared to the learning to deal with spoken language, and learning to interact constructively with others. There are plenty of people who know how to read and write, but don't know how to relate to society, and many of them have been to head start. If the basic foundation of a stable personality has been laid, reading and writing can easily be added. Manson and McVeigh, and Harris and Clebold all knew how to read and write.
A society that can't spare the time of mothers to teach and nurture children is a society that puts a very low priority on the training of its future generations.