Interesting idea... Is human morality (in situations where no punishment exists) a result of the societies we live in and our societal expectations, our upbringing, or is there some inherent morality (guilt from doing something bad, or satisfaction from doing the right thing) within most people?
Whilst I do live somewhere that has trolleys with coins, sometimes you get one that is damaged and doesn't require a coin. Yet I still return those ones, because why wouldn't I? It only takes a minute.
Well yeah, but also a bit more than that - even after growing up, does society itself have some impact? Even if someone was raised really well, I feel like they could change over time depending on what society tells them is appropriate.
Typically "nurture" includes those things. You're right though - it isn't just our parents and childhood, it's everybody through our whole lives. We only stop changing when we die.