[Gollum]

In my campaigns, no advantage is purely inborn. Empathy, for instance, could be aquired after the character creation, with a good reason for that. Indeed, some major events in your life can open your soul to others, and make you suddenly have a good empathy...

So, if the player has a good reason (and enough bonus character points to spend), I can allow him to buy empathy between two adventures...

having said that, aquiring an advantage this way is not really "learning" it. In my humble opinion, once can learn skills or techniques, but not advantages (except, of course, advantages that are just advantages for game purpose, like languages for instance).