The possessive dative construction has been widely adopted as an unaccusativity diagnostic (Borer and Grodzinsky 1986). Gafter (2014) casts doubt on the relevance of unaccusativity to the acceptability of the construction. We conducted a series of acceptability judgment experiments to investigate the validity of the possessive dative construction as an unaccusativity diagnostic, controlling for possible confounds such as animacy, definiteness, plausibility, lexical choice, type of possession, and context salience. The experiments revealed that possessive datives are significantly more acceptable with unaccusative verbs than with unergatives, including reflexive and emission verbs. We conclude that unaccusatives, but not unergatives, are grammatical in the construction, and we defend a structural account of the data.

The article sheds new light on the so-called dative dispositional construction in Russian. We revise the characterization of the classes of verbs able to feed the construction, showing that its input is best defined in terms of the Theta System (Reinhart’s ( 2002 , 2016 ) approach to thematic relations). To resolve controversies in the literature regarding the licensing conditions of the construction and its possible interpretations, we ran two surveys whose design and findings we report. We then discuss the properties of the construction comparatively, define the operation deriving it, and provide evidence that the operation is lexical. This has consequences regarding the nature of the lexical component.

We argue that crosslinguistic variation regarding verbal reflexivization is parametric, reflecting a broader lexicon-syntax parameter: arity operations—operations on θ-roles, which affect the valence of a predicate—can apply in the lexicon or in the syntax. The significant empirical coverage of this parameter supports the view that the lexicon must be an active component of the grammar. The discussion focuses mainly on the formation of reflexive verbs. We argue that the prevailing view that reflexive verbs have an unaccusative derivation cannot be maintained. Rather, the reflexivization operation bundles a θ-role with an external θ-role, forming a combination that must merge externally. Next, we also briefly review other arity operations: (a) reciprocalization, (b) decausativization, and (c) saturation, which is involved in the formation of passives, middles, and impersonals. Variation in auxiliary selection, owing to the application of reflexivization or other arity operations, is independent of the lexicon-syntax parameter and follows under our approach from a structural accusative Case parameter.