I was hesitant to make any concrete claims in my comment since I don't know much about it but I _think_ this is basically about The Method i.e. Method Acting.
From what I understand, although people still talk about it as if it's a specialised or niche thing, it's actually basically just how acting is done nowadays (at least for films and in the west).
From what I understand, although people still talk about it as if it's a specialised or niche thing, it's actually basically just how acting is done nowadays (at least for films and in the west).