This finding supports the growing evidence for systematic differences in representation and/or similarity operations between abstract and concrete concepts (Hill, Kiela, and Korhonen 2013), and suggests that at least part of these concreteness effects are independent of POS.
it appears that models built from underlying vectors of co-occurrence counts, such as VSMs and SVD, are better equipped to capture the semantics of concrete entities, whereas the embeddings learned by NLMs can better capture abstract semantics.