Linguistic analyses suggest that there are two types of intransitive verbs: unaccusatives, whose sole argument is a patient or theme (e.g., fall ), and unergatives, whose sole argument is an agent (e.g., jump ). 1 Past psycholinguistic experiments suggest that this distinction affects how sentences are processed: for example, it modulates both comprehension processes ( Bever and Sanz 1997 , Friedmann et al. 2008 ) and production processes ( Kegl 1995 , Kim 2006 , M. Lee and Thompson 2004 , J. Lee and Thompson 2011 , McAllister et al. 2009 ). Given this body of evidence, it is reasonable to assume, as we do here, that this distinction is directly relevant to psycholinguistic theorizing. However, especially in production, exactly how this distinction affects processing is unknown, beyond the suggestion that unaccusatives somehow involve more complex processing than unergatives (see J. Lee and Thompson 2011 ). Here we examine how real-time planning processes in production differ for unaccusatives and unergatives. We build on previous studies on lookahead effects in sentence planning that show that verbs are planned before a deep object is uttered but not before a deep subject is uttered ( Momma, Slevc, and Phillips 2015 , 2016 ). (We use terms like deep subject in a theory-neutral fashion, with no intended commitment to a specific syntactic encoding.) This line of research sheds light on the broader issue of how the theory of argument structure relates to sentence production.

Children have repeatedly been found to exhibit Principle B violations, with some reports that these violations occur only with nonquantified antecedents. This quantificational asymmetry (QA) in the delay of Principle B effect (DPBE) has been taken as support for a theory that restricts the scope of binding theory to bound variable anaphora (Reinhart 1983). However, the QA has been challenged, on the basis of discrepant findings and methodological concerns (Elbourne 2005). Here, we resolve the status of the QA with 3 studies and a review of over 30 previous studies. Using improved experimental materials, we show that children disallow local pronoun binding with both referential and quantificational antecedents when Principle B is at issue (Experiment 1), but not when Principle B is neutralized (Experiment 2). When methodological flaws are reintroduced, we replicate the QA (Experiment 3). Drawing on evidence from adult language processing, we suggest that the role of Principle B as a filter on representations during sentence understanding, in concert with pragmatic infelicities in the tasks used, accounts for the wide variability in the DPBE in the literature.

This article presents a series of arguments that syntactic structures are built incrementally, in a strict left-to-right order. By assuming incremental structure building it becomes possible to explain the differences in the range of constituents available to different diagnostics of constituency, including movement, ellipsis, coordination, scope, and binding. In an incremental derivation structure building creates new constituents, and in doing so it may destroy existing constituents. The article presents detailed evidence for the prediction of incremental grammar that a syntactic process may refer only to those constituents that are present at the point in the derivation when the process applies.