Ava Irani will be defending her dissertation proposal on Friday, March 16th at noon. The
defense will be held in the Linguistics Library (3rd
floor, 3401-C Walnut Street Suite 300, C Wing).
The link to her proposal can be found here <http://avairani.net/files/Irani_proposal_learning_from_positive_evidence.pdf>.
The abstract is below.
*(Working) Title:*Learning from Positive Evidence: The Case of Verb Argument Structure and the Problem of Overgeneralization
*Advisor:*Julie Anne Legate
*Proposal Committee:*Charles Yang, Kathryn Schuler, Robin Clark
This dissertation examines the way in which children learn verb argument structure through positive evidence in the input. We examine the acquisition of raising and control constructions, the acquisition of causatives, and the acquisition of passives. Throughout this dissertation, I evaluate theories of language acquisition that rely on indirect negative evidence (Ambridge et al. 2008; Becker 2014; Bowerman and Croft 2008; i.a.), and show that these approaches cannot adequately account for the learner's developmental timeline. I also discuss the problem of overgeneralization (Baker 1979), which refers to instances where children overgeneralize a rule, creating a superset grammar. Adopting Yang's (2016) Sufficiency Principle, I show that children generalize rules in their grammar when there is sufficient evidence in the input, and they retreat from their generalization when there is insufficient evidence in the primary linguistic data.
First, I address the acquisition of two kinds of verbs: raising verbs that do not introduce an external argument, and control verbs that do. I show that children can differentiate these verbs using positive evidence in the input in the form of non-referential expletive subjects. I argue against indirect negative evidence approaches (e.g. Becker 2014) that claim for the acquisition of control predicates through the absence of inanimate subjects with control verbs. I also address the use of indirect negative evidence in accounting for the overgeneralization of the causative alternation rule (Ambridge et al. 2008; Bowerman & Croft 2008; Pinker 1989). I show that there is no effect of statistical preemption in the unlearning of the causative rule. Furthermore, I provide evidence against entrenchment accounts, which claim that if a verb is heard in an intransitive frame enough times, the learner will assume that it can only occur as an intransitive. I argue against this approach by showing that verb frequency alone cannot account for the overgeneralization of the causative rule, and the retreat from overgeneralization. Finally, I discuss the acquisition of passives, which have been argued to be acquired late in English (e.g. Wexler 2004). I argue that children's knowledge and use of passives is directly reflected in the input they receive. I present novel child data of early passive use in English, and show that the low frequency of their occurrence is due to the low frequency of English passives in the input. Using the Sufficiency Principle, I also present an account of when the passive in English is acquired by the learner. The aforementioned cases together show that children's mastery of verb argument structure is reflective of the evidence available to them in the primary linguistic data.