According to McGowan, moral development research shows that thinking critically about rules creates far more powerful moral reasoners; kids are far more likely to generate better rules for themselves if they learn and understand the reasons behind why something is right or wrong, rather than by simply following orders.
McGowan mentions a book by Samuel and Pearl Oliner, called The Altruistic Personality: Rescuers of Jews in Nazi Europe. The Oliners conducted 700 interviews in order to answer an important question: why did some people (the 'rescuers') in Nazi Europe risk their lives to help Jews, while others (the 'non-rescuers') stood passively by, doing nothing?
One of the fascinating conclusions of their study was that the person’s willingness to assist Jews in need was, among other reasons, determined by the type of moral upbringing they received from their parents. Rescuers were more likely to have had parents who depended on moral reasoning rather than physical punishment to teach concepts of right and wrong. Non-rescuers, however, were more likely to have grown up in households where authoritarianism was prominent.
From page 179:
Parents whose disciplinary techniques are benevolent, particularly those who rely on reasoning, are more likely to have kind and generous children, children who behave helpfully with respect to others . . . inductive reasoning is particularly conductive to altruism. Induction forces children’s attention on the consequences of their behaviors for others, drawing attention to other’s feelings, thoughts and welfare.
A similar conclusion was reached in a separate, but similar study:
Most rescuers had compassionate and loving families. Their parents taught them the difference between right and wrong through logic-based decision making rather than authoritatively forcing the decision on them.
Studies like these highlight the importance of moral reasoning in developing kindness, generosity and alturism in children.