The division of labor in explanations of verb phrase ellipsis

In this paper, we will argue that, of the various grammatical and discourse constraints that affect acceptability in verb phrase ellipsis (VPE), only the structural parallelism constraint is unique to VPE. We outline (previously noted) systematic problems that arise for classical structural accounts of VPE resolution, and discuss efforts in recent research on VPE to reduce explanations of acceptability in VPE to general well-formedness constraints at the level of information structure (e.g. Kehler in Linguist Philos 23(6):533-575, 2000; Coherence, reference and the theory of grammar, CSLI Publications, Stanford, 2002; Proceedings of semantics and linguistic theory, vol 25, 2015; Kertz in Language 89(3):390-428, 2013). In two magnitude estimation experiments, we show that—in line with Kehler's predictions—degradation due to structural mismatch is modulated by coherence relation. On the other hand, we consistently find residual structural mismatch effects, suggesting that the interpretation of VPE is sensitive to structural features of the VPE antecedent. We propose that a structural constraint licenses VPE, but that sentences violating this constraint can nevertheless be interpreted. The variability in acceptability is accounted for not by additional constraints on VPE in the grammar, but by the numerous general biases that affect sentence and discourse well-formedness, such as information structural constraints (as proposed by Kertz 2013), discourse coherence relations (Kehler 2000), sensitivity to Question Under Discussion structure (e.g. Ginzburg and Sag in English interrogative constructions, CSLI Publications, Stanford, 2000; Kehler 2015), and thematic role bias at the lexical level (e.g. McRae et al. in J Mem Lang 38:283-312, 1998). We test the prediction that thematic role bias (Experiment 3) and QUD structure (Experiment 4) will influence both elliptical and non-elliptical sentences alike, while structural mismatch continues to degrade elliptical sentences alone. Our proposal differs from existing proposals in cutting the explanatory pie in a different way with respect to how variations in acceptability are accounted for. We suggest that degradation can result from at least two distinct and separable sources: violating construction-specific grammatical constraints, or from complexity differences in interpretation related to very general discourse level information.