When I was first told that strings were able to see Einstein equations I thought, "what is the deal?". The Riemann Curvature Tensor is a two dimensional object, nothing rare you capture it by using two dimensional objects. It is well known so it is not rare that high level books do not mention it. But now I am checking some of these "string for undergraduate" stuff and it is not mentiones neither, so perhaps it is not a valid argument. Has anybody seen some paper approaching to stringgy gravity from this perspective? The closest thing I have seen is Connes observation that the Poliakov action is a two dimensional object and that its Dixmier trace in n dimensions is always proportional to Einstein-Hilbert action.