Doctoral Dissertation Research: Intervention Effects in the Acquisition of Passives

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

In passive sentences such as 'The mouse was chased by the cat', the undergoer of an action is expressed as the subject of the sentence (here, 'the mouse'). Previous studies have found that in many languages children’s learning of passives occurs late in the language acquisition process, but not all types of passives are acquired equally late. 'Long' passives – those in which the agent is expressed ('the cat' above) – are more difficult for young children to understand and less frequently produced than 'short' passives – those in which the agent is left implicit (as in, ‘The mouse was chased’). This dissertation investigates why passives, especially long passives, are difficult for children. Following theoretically-based predictions, we will test whether children's difficulty is reduced when the two nouns are more distinct (e.g., one is singular and the other plural). Our experimental results will provide a developmental timeline that speech-language professionals can use as a reference to determine whether a child is delayed in the acquisition of passives and/or whether s/he suffers from a language disorder. Understanding why passives are difficult can aid the development of better materials to treat children with language delays as well as people suffering from agrammatic aphasia, who also have difficulties with passives. This project also provides opportunities for undergraduate students to partake in experimental research and data analysis, thereby training the next generation of scientists. This dissertation examines 3- to 6-year-old children's acquisition of passives via 3 behavioral experiments and statistical analysis of a large body (corpus) of previously collected data. The corpus study describes and compares children's production of passives with passives in their caretakers' speech, using data from CHILDES (MacWhinney 2000) to understand the role of language input in the process of passive acquisition. The behavioral experiments focus on children's comprehension of passives. Experiment 1 aims to compare children's understanding of active sentences, long passives, and short passives in a picture-selection task. Experiments 2 and 3 use the same technique to investigate the role of two properties of nouns that are potential factors in the acquisition of passives. This research provides a more comprehensive study of passive acquisition than is available in the existing literature, improving our understanding of how children learn language, and it helps to adjudicate between competing theories of grammar that make opposing predictions about the outcome of the passive comprehension experiments, yielding insight into how human language works. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.