Virtue only Possible via External Feedback?

On page 143, Adams states that “it seems unlikely that any child makes much progress in virtue, or even life, without learning to be reasonably good at a number of social roles.” Adams does not exactly say it and probably has a more nuanced position, but this could be taken to mean that Adams thinks virtue to be impossible or nearly so without social interaction. Clearly, this position leaves open the possibility of introspection having an important role in virtue. Upon closer consideration, though, I have decided that virtue (at least using the definition of Adams) is probably impossible without some form of social role, as social roles are the inevitable consequences of even the minutest form of human interaction.
Adams has elsewhere stated that self-regard plays an important factor in virtue. Consider, then, a case in which a baby was born into a world with no one else present. He was taken care of by a non-sentient robot that ensured that the baby lived until it reached the stage where he could take care of himself. He was then released into the wild. It would seem that any virtue the baby might have would probably stem from the goal of self-preservation, and would be concerned with self-preservation. However, virtue, at least according to Adams is concerned with excellence, and nothing seems particularly excellent (or, to use Adams’s definition, worthy of admiration regarding intrinsic goodness) about the self-preservation instincts of a feral child. On the other hand, highly valuing all life might lead to the view that even those uncritical instincts have some excellence.