"...When mothers deign to nurse their own children, then will be a reform in morals; natural feeling will revive in every heart; there will be no lack of citizens for the state; this first step by itself will restore mutual affection."
Jean Jacques Rousseau
Ask any new parent: there are as many opinions on how to raise children as there are people. What children should eat, where they should sleep, and how they should be educated have been the subjects of debate for centuries.
John Locke and Jean Jacques Rousseau, two philosophers of the eighteenth century, entered into this argument on opposing sides. Locke stressed the influence of environment on child development. He famously described a child's mind as "white Paper, devoid of all Characters," allowing a few innate tendencies but, for the most part, "Wax, to be moulded and fashioned as one pleases."
Rousseau, on the other hand, thought children were born with natural inclinations which are inherently good. Rousseau refuted the idea of original sin and denied that children should be shaped according to societal norms. He was among the first to recognize that children are not miniature adults, but are instead at different stages of development. His philosophy incorporates both preformation and epigenesis: the child is born with a set of fixed characteristics, unique to himself, but the environment in which he develops is vitally important.
One of Rousseau’s legacies was an exhortation that mothers should breastfeed their own children rather than hiring a wet nurse - not for nutritional reasons, but to strengthen the natural attachment between mother and child. Scientists have explored the role of breastfeeding in child development ever since. In the late eighteenth and early nineteenth centuries, nursing mothers were warned that shock or emotional upset could poison their milk, resulting in illness for their infants. Babies were better off with a hired nurse of stable character, doctors advised, if the mother was of a nervous temperament. By the early twentieth century, psychologists warned of the negative emotional effects of early weaning and stressed the importance of prolonged breastfeeding in the development of personality.
Epigenetics researchers continue to study the effects of early childhood experiences on adulthood, particularly the relationship between parent and child. Studies on rats have shown that those with loving mothers have epigenetic markers that allow them to handle stress better as adults. Similarly, changes in a gene that plays a role in the body’s response to stress have been observed in the adult victims of child abuse.