Matthew Traxler - US grants

DESCRIPTION (provided by applicant): The specific aim of the proposed research is to determine how individual differences in working-memory capacity affect sentence understanding. Some current theories assume that the cognitive processes involved in sentence interpretation are modular. Other theories assume that the language processing architecture is highly interactive. According to these latter accounts, sentence interpretation can be influenced by any number of factors, including working memory restrictions. Individual differences in sentence-interpretation strategies are thus more compatible with the latter class of account than the former. Identifying how and why working memory limitations affect sentence understanding helps distinguish between accounts of sentence-interpretation that have been developed on the basis of normative data. Measures of verbal-working-memory capacity tend to correlate with measures of reading comprehension skill and indices of academic achievement, such as verbal SAT scores. Hence, samples of low-capacity participants will contain substantial numbers of people who lag behind their peers in reading comprehension and academic achievement. The experiments in the current proposal will help determine what strategies low-capacity comprehenders adopt to process and comprehend sentences. This knowledge may lead to insights that will help practitioners devise better ways of intervening with under-achieving populations.

The goal of this research project is to understand the representations and processes behind syntactic priming. Syntactic priming occurs when processing the syntax of one sentence facilitates the processing of a related syntactic structure in another sentence later in the discourse. This research will test the hypothesis that syntactic priming is caused by two different types of mental processes, one that operates over short time scales (a few seconds) and another that operates over longer time scales (a few minutes to several days). This dual-mechanism hypothesis proposes that 1) transient increases in activation of syntactic representations that are tied to specific words produce short-term priming effects and 2) reorganizations of long-term memory produce longer-lived changes in the relative strength of different syntactic representations, which in turn produce long-term priming effects.

The proposed experiments use behavioral and neurophysiological research methods to test the dual-mechanism account. These methods have complementary strengths but both are highly sensitive to momentary changes in cognitive processing load. Using both methods in parallel gives the potential to illuminate the mental processes that give rise to neurophysiological responses. In addition, the proposed research may contribute to our understanding of adult language learning, in particular, changes in the adult system of syntactic representations and parsing processes as learning proceeds. This in turn may suggest ways in which poor readers can improve their reading skill. The project will also provide training opportunities for graduate students.

This proposal requests NSF funding to support students and distinguished speakers for a special session on sentence processing at the CUNY Conference on Human Sentence Processing to be held in March 2009 at the University of California, Davis. To understand how people speak and comprehend language, researchers need to consider how speaking and comprehension influence each other. Currently, language researchers tend to treat understanding and speaking as separate phenomena, and they build separate theories to handle the two domains. Although substantial progress has been made in developing theories of language understanding and speech even when the two are investigated separately, a better understanding is possible if researchers consider how production affects comprehension and vice versa. The immediate goal of this project is to foster communication between researchers who study production and researchers who study comprehension with the further goals of 1) encouraging and developing collaboration between researchers in language comprehension and language production, 2) advancing linguistic and psycholinguistic theory by encouraging researchers to include connections between comprehension and production in their models, and 3) to promote research that integrates concepts from production and comprehension so that the resulting theories provide a more comprehensive description of human language.

The CUNY Conference on Human Sentence Processing is one of the most prominent and successful meetings for researchers interested in experimental psycholinguistics and sentence processing. The proposed special session of the 22nd Annual CUNY Conference on Human Sentence Processing will create a number of important and unique opportunities for language researchers by bringing them into contact with highly successful scholars whose work bridges the gap between speech and language comprehension. The special session will involve researchers from multiple disciplines to foster interdisciplinary research and promote new and exciting collaborations. The funding will also help graduate students to participate in the meeting in various ways, including reduced fees and opportunities for travel support. Finally, the invited speakers include members of underrepresented minorities.

? DESCRIPTION (provided by applicant): Achieving high levels of reading proficiency in the deaf population has resisted our best efforts in both research and practice [1]. Progress in this area is limited by the lack of basic science research that focuses on deaf readers. In particular, we know almost nothing about syntactic processing of English in deaf readers. The immediate goal of the proposed research is to uncover basic facts about on-line processing and comprehension of English sentences in this population. The long-range goal is to use this knowledge to design more effective materials and methods to enhance literacy. Thus, the proposed research furthers NIH's mission of seeking fundamental knowledge about the nature and behavior of living systems and applying that knowledge to enhance health and reduce the burdens of illness and disability. The specific aims of the project include the following: (1) to investigate the effects of syntactic complexity on processing time and comprehension in deaf readers; (2) to investigate how individual differences moderate the effects of syntactic complexity on processing time and comprehension. The proposed experiments manipulate syntactic properties of English sentences and measure the effects of those manipulations on patterns of eye-movements during reading. Comprehension outcomes are also assessed. We will contrast performance in deaf readers, hearing Chinese-English bilingual readers who have English as a second language, and hearing native English readers. The chief dependent measures will be fixation times and responses to comprehension questions. These data will allow us to determine how much difficulty deaf readers have processing and interpreting sentences of different syntactic types. In addition to collecting outcome data, we will collect demographic data and indices of individual skills and knowledge, including executive function, working memory capacity, English vocabulary, and oral communication ability. We will apply mulitilevel modeling techniques [9, 69] to assess how individual reader characteristics and text characteristics interact to determine processing and comprehension outcomes. The results of the proposed experiments will have implications for psycholinguistic theories of syntactic processing in deaf and hearing bilinguals and will extend the investigation of individual differences in sentence processing among hearing native English speakers. The results of these experiments will inform the design of further experiments investigating sentence processing in deaf readers. The knowledge gained from these experiments will inform efforts to construct improved materials and methods for developing literacy skill in deaf readers. The findings may also have relevance for problems in hearing readers that relate to phonological processes.

PROJECT SUMMARY/ABSTRACT Natural products from bacteria have long been the frontline defense in the struggle against bacterial infections, and have also found wide use as antifungals, anthelminthics, anti-cancer drugs, and immunosupressants. One group of bacteria, the actinomycetes, has historically been the deepest source of clinically-useful natural products. Recent work has demonstrated that natural product biosynthesis often results from microbial communication in the form of interactions between cells in colonies of a single actinomycete, or by interactions with microbes of different species. Together, these observations underscore the idea that induction of natural product biosynthesis is socially-driven. The goal of this study is to understand how inter- and intra- species interactions activate natural product biosynthesis at a molecular level. Our first research objective seeks a mechanistic understanding of how a model actinomycete, Streptomyces coelicolor, activates expression of genes for natural product biosynthesis in the presence of other actinomycetes. We have found that this activation requires an unusual and poorly-understood signal transduction mechanism found in actinomycetes that shares parallels with eukaryotic systems that rely on G protein activation. Our second research objective seeks a systems-level understanding of natural product biosynthesis in S. coelicolor within the context of cell fate decisions. Knowledge generated from this objective may be employed to someday manipulate cell fates within actinomycete cultures to drive natural products discovery and production. These objectives run in parallel with our efforts to build a microfluidic device for studying microbial interspecies interactions with unprecedented speed, throughput, and specificity. This device will have multiple applications related to our first two objectives and beyond. This research will illuminate the social aspect of natural product biosynthesis, and in the long term, provide a foundation for harnessing microbial social cues and genetic regulation to maximize future natural products discovery efforts. !