Some additional resources re: moral development in children and adults:
… I hope you too are well and your mamma, and that you are always obedient to Papa and Matro, as you used to be. Let me tell you that the reason that I and all the rest of us love you is that you are always obedient to them. – Epicurus, in his Letter to a Boy or Girl
(from the Epicurean fragments at epicurus dot net, my link does not work but not sure if its because of the website or if it's because am at work computer)
Also, I drew a parallel between Epicurean and Confucian ideas regarding the importance of role models / mentors for character development. Confucius argued that when leaders are corrupt or evil, people may obey out of fear, but when they're virtuous they wish to avoid the shame of disappointing them. From the above statement by Epicurus to a child, it seems like Epicurus sought to be a virtuous presence that children are ashamed to disappoint, instead of a feared one.
http://societyofepicurus.com/reasonings-abo…ucius-analects/
Synopsis of Epicurus’ “On Nature”, Book 25: On Moral Development - which mentions neuroplasticity, or the physical changes to our brain through habituation and character development, which is true to a materialist interpretation of soul development.
http://societyofepicurus.com/synopsis-of-ep…al-development/
(at the bottom of the essay, this includes a link to
Moral Responsibility and Moral Development in Epicurus, by
Susanne Bobzien)