On the difficulty of making concreteness concrete

The use of labels of semantic properties like `concreteness' is quite common in studies in syntax, but their exact meaning is often unclear. In this article, we compare different denitions of concreteness, and use them in dierent implementations to annotate nouns in two data sets: (1) all nouns with word sense annotations in the SemCor corpus, and (2) nouns in a particular lexico-syntactic context, viz. the theme (e.g. a book) in prepositional dative (gave a book to him) and double object (gave him a book) constructions. The results show that the denition and implementation used in dierent approaches differ greatly, and can considerably aect the conclusions drawn in syntactic research. A follow-up crowdsourcing experiment showed that there are instances that are clearly concrete or abstract, but also many instances for which humans disagree. Therefore, results concerning concreteness in syntactic research can only be interpreted when taking into account the annotation scheme used and the type of data that is being analysed.