Why 8?

Forgive me for posing a question, and having no answer whatsoever, but was doing some reading this morning about initiation rituals into adulthood, which lead me to wonder about the LDS “age of accountability.” Anecdotally, I’d say that the most common age for the entrance into adulthood is around the ages of puberty, from 12-14. The obvious bodily changes and sexual maturation signify the time to be inducted into adulthood. In modern societies, with the delayed childhood that modernity introduced, adulthood is often put off until 16, 18, or 21. The rituals that attend these age milestones are less formalized, but still exist, whether it is driving, the cessation of free state-sponsored education, or other legal privileges and responsibilities that arrive.

As time moves on, adulthood is delayed further and further, and childhood is extended, romanticized, and protected. While 8 may have once seemed a ripe old age where children could have been expected a certain level of accountability, today that idea seems rather problematic, and the explanation to outsiders that 8 year olds choose to be baptized of their own free will lacks a certain credibility.

All of this leads me to wonder why LDS tradition arrived at 8 as the age of accountability in the first place. Did that age ever enjoy a degree of expected adulthood and accountability? Where there other early American religious or political traditions that would help situate this choice? Why not puberty or other early American ages of accountability, like the age one could join the army, for instance? Does anyone know?